From a35ed94359409f813648fb50351a37d3240c61fc Mon Sep 17 00:00:00 2001
From: m7pr <m7pr@users.noreply.github.com>
Date: Tue, 22 Oct 2024 15:07:03 +0000
Subject: [PATCH] deploy: b3358c1870dfc077c30e342e9e5e2e44f67be742

---
 main/coverage-report/index.html | 12203 +++++++++++-------------------
 1 file changed, 4506 insertions(+), 7697 deletions(-)

diff --git a/main/coverage-report/index.html b/main/coverage-report/index.html
index 3d846750a..c1aaa5adb 100644
--- a/main/coverage-report/index.html
+++ b/main/coverage-report/index.html
@@ -95,7 +95,7 @@
   font-size: 11px;
 }</style>
   <div class="col-md-8 col-md-offset-2">
-    <h2>teal.data coverage - 89.08%</h2>
+    <h2>teal.data coverage - 84.93%</h2>
     <div class="tabbable">
       <ul class="nav nav-tabs" data-tabsetid="covr">
         <li class="active">
@@ -107,75 +107,75 @@ <h2>teal.data coverage - 89.08%</h2>
       </ul>
       <div class="tab-content" data-tabsetid="covr">
         <div class="tab-pane active" title="Files" data-value="Files" id="tab-covr-1">
-          <div class="datatables html-widget html-fill-item" id="htmlwidget-bc6b83836679de1fb7ed" style="width:100%;height:500px;"></div>
-          <script type="application/json" data-for="htmlwidget-bc6b83836679de1fb7ed">{"x":{"filter":"none","vertical":false,"fillContainer":false,"data":[["<a href=\"#\">R/deprecated.R<\/a>","<a href=\"#\">R/teal_data-show.R<\/a>","<a href=\"#\">R/dummy_function.R<\/a>","<a href=\"#\">R/teal_data.R<\/a>","<a href=\"#\">R/verify.R<\/a>","<a href=\"#\">R/join_keys-utils.R<\/a>","<a href=\"#\">R/teal_data-class.R<\/a>","<a href=\"#\">R/utils-get_code_dependency.R<\/a>","<a href=\"#\">R/join_keys-extract.R<\/a>","<a href=\"#\">R/formatters_var_labels.R<\/a>","<a href=\"#\">R/join_key.R<\/a>","<a href=\"#\">R/join_keys-print.R<\/a>","<a href=\"#\">R/topological_sort.R<\/a>","<a href=\"#\">R/join_keys-parents.R<\/a>","<a href=\"#\">R/testhat-helpers.R<\/a>","<a href=\"#\">R/join_keys.R<\/a>","<a href=\"#\">R/teal_data-datanames.R<\/a>","<a href=\"#\">R/join_keys-names.R<\/a>","<a href=\"#\">R/teal_data-get_code.R<\/a>","<a href=\"#\">R/join_keys-c.R<\/a>","<a href=\"#\">R/cdisc_data.R<\/a>"],[345,20,16,69,114,154,98,455,280,127,91,61,64,136,55,160,68,32,130,42,38],[56,4,2,24,37,67,25,156,113,53,33,31,28,28,22,21,18,15,12,10,1],[0,0,0,12,28,64,24,155,113,53,33,31,28,28,22,21,18,15,12,10,1],[56,4,2,12,9,3,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0],["0","0","0","48","1","61","85","181","126","13","845","13","348","233","36","258","54","3","48","196","1"],["0.00%","0.00%","0.00%","50.00%","75.68%","95.52%","96.00%","99.36%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%"]],"container":"<table class=\"row-border\">\n  <thead>\n    <tr>\n      <th>File<\/th>\n      <th>Lines<\/th>\n      <th>Relevant<\/th>\n      <th>Covered<\/th>\n      <th>Missed<\/th>\n      <th>Hits / Line<\/th>\n      <th>Coverage<\/th>\n    <\/tr>\n  <\/thead>\n<\/table>","options":{"searching":false,"dom":"t","paging":false,"columnDefs":[{"targets":6,"createdCell":"function(td, cellData, rowData, row, col) {\n  var percent = cellData.replace(\"%\", \"\");\n  if (percent > 90) {\n    var grad = \"linear-gradient(90deg, #edfde7 \" + cellData + \", white \" + cellData + \")\";\n  } else if (percent > 75) {\n    var grad = \"linear-gradient(90deg, #f9ffe5 \" + cellData + \", white \" + cellData + \")\";\n  } else {\n    var grad = \"linear-gradient(90deg, #fcece9 \" + cellData + \", white \" + cellData + \")\";\n  }\n  $(td).css(\"background\", grad);\n}\n"},{"className":"dt-right","targets":[1,2,3,4]},{"name":"File","targets":0},{"name":"Lines","targets":1},{"name":"Relevant","targets":2},{"name":"Covered","targets":3},{"name":"Missed","targets":4},{"name":"Hits / Line","targets":5},{"name":"Coverage","targets":6}],"order":[],"autoWidth":false,"orderClasses":false},"callback":"function(table) {\ntable.on('click.dt', 'a', function() {\n  files = $('div#files div');\n  files.not('div.hidden').addClass('hidden');\n  id = $(this).text();\n  files.filter('div[id=\\'' + id + '\\']').removeClass('hidden');\n  $('ul.nav a[data-value=Source]').text(id).tab('show');\n});\n}"},"evals":["options.columnDefs.0.createdCell","callback"],"jsHooks":[]}</script>
+          <div class="datatables html-widget html-fill-item" id="htmlwidget-bd084837d5b4b87ff108" style="width:100%;height:500px;"></div>
+          <script type="application/json" data-for="htmlwidget-bd084837d5b4b87ff108">{"x":{"filter":"none","vertical":false,"fillContainer":false,"data":[["<a href=\"#\">R/deprecated.R<\/a>","<a href=\"#\">R/teal_data-show.R<\/a>","<a href=\"#\">R/dummy_function.R<\/a>","<a href=\"#\">R/teal_data-get_code.R<\/a>","<a href=\"#\">R/teal_data.R<\/a>","<a href=\"#\">R/verify.R<\/a>","<a href=\"#\">R/join_keys-utils.R<\/a>","<a href=\"#\">R/teal_data-class.R<\/a>","<a href=\"#\">R/join_keys-extract.R<\/a>","<a href=\"#\">R/formatters_var_labels.R<\/a>","<a href=\"#\">R/join_key.R<\/a>","<a href=\"#\">R/join_keys-print.R<\/a>","<a href=\"#\">R/join_keys-parents.R<\/a>","<a href=\"#\">R/topological_sort.R<\/a>","<a href=\"#\">R/testhat-helpers.R<\/a>","<a href=\"#\">R/join_keys.R<\/a>","<a href=\"#\">R/teal_data-datanames.R<\/a>","<a href=\"#\">R/join_keys-names.R<\/a>","<a href=\"#\">R/join_keys-c.R<\/a>","<a href=\"#\">R/cdisc_data.R<\/a>"],[345,20,16,130,69,114,154,98,280,127,91,61,136,64,55,160,68,32,42,38],[56,4,2,12,24,37,67,25,113,53,33,31,28,28,22,21,18,15,10,1],[0,0,0,5,12,28,64,24,113,53,33,31,28,28,22,21,18,15,10,1],[56,4,2,7,12,9,3,1,0,0,0,0,0,0,0,0,0,0,0,0],["0","0","0","1","24","1","61","42","126","13","845","13","232","326","36","244","32","3","196","1"],["0.00%","0.00%","0.00%","41.67%","50.00%","75.68%","95.52%","96.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%","100.00%"]],"container":"<table class=\"row-border\">\n  <thead>\n    <tr>\n      <th>File<\/th>\n      <th>Lines<\/th>\n      <th>Relevant<\/th>\n      <th>Covered<\/th>\n      <th>Missed<\/th>\n      <th>Hits / Line<\/th>\n      <th>Coverage<\/th>\n    <\/tr>\n  <\/thead>\n<\/table>","options":{"searching":false,"dom":"t","paging":false,"columnDefs":[{"targets":6,"createdCell":"function(td, cellData, rowData, row, col) {\n  var percent = cellData.replace(\"%\", \"\");\n  if (percent > 90) {\n    var grad = \"linear-gradient(90deg, #edfde7 \" + cellData + \", white \" + cellData + \")\";\n  } else if (percent > 75) {\n    var grad = \"linear-gradient(90deg, #f9ffe5 \" + cellData + \", white \" + cellData + \")\";\n  } else {\n    var grad = \"linear-gradient(90deg, #fcece9 \" + cellData + \", white \" + cellData + \")\";\n  }\n  $(td).css(\"background\", grad);\n}\n"},{"className":"dt-right","targets":[1,2,3,4]},{"name":"File","targets":0},{"name":"Lines","targets":1},{"name":"Relevant","targets":2},{"name":"Covered","targets":3},{"name":"Missed","targets":4},{"name":"Hits / Line","targets":5},{"name":"Coverage","targets":6}],"order":[],"autoWidth":false,"orderClasses":false},"callback":"function(table) {\ntable.on('click.dt', 'a', function() {\n  files = $('div#files div');\n  files.not('div.hidden').addClass('hidden');\n  id = $(this).text();\n  files.filter('div[id=\\'' + id + '\\']').removeClass('hidden');\n  $('ul.nav a[data-value=Source]').text(id).tab('show');\n});\n}"},"evals":["options.columnDefs.0.createdCell","callback"],"jsHooks":[]}</script>
         </div>
         <div class="tab-pane" title="Source" data-value="Source" id="tab-covr-2">
           <div id="files">
-            <div id="R/join_keys-extract.R" class="hidden">
+            <div id="R/testhat-helpers.R" class="hidden">
               <table class="table-condensed">
                 <tbody>
                   <tr class="never">
                     <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname join_keys</pre>
+                      <pre class="language-r">#' Test if two objects are (nearly) equal</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @order 2</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' `all.equal(target, current)` is a utility to compare `join_keys` objects target</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @section Functions:</pre>
+                      <pre class="language-r">#' and current testing `near equality`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">5</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - `x[datanames]`: Returns a subset of the `join_keys` object for</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">6</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' given `datanames`, including parent `datanames` and symmetric mirror keys between</pre>
+                      <pre class="language-r">#' If they are different, comparison is still made to some extent, and a report</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">7</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' `datanames` in the result.</pre>
+                      <pre class="language-r">#' of the differences is returned.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">8</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - `x[i, j]`: Returns join keys between datasets `i` and `j`,</pre>
+                      <pre class="language-r">#' Do not use `all.equal` directly in if expressions—either use `isTRUE(all.equal(....))`</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">9</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   including implicit keys inferred from their relationship with a parent.</pre>
+                      <pre class="language-r">#' or identical if appropriate.</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -189,14 +189,14 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">11</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param i,j indices specifying elements to extract or replace. Index should be a</pre>
+                      <pre class="language-r">#' The parents attribute comparison tolerates `NULL` and empty lists and will find</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">12</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' a character vector, but it can also take numeric, logical, `NULL` or missing.</pre>
+                      <pre class="language-r">#' no difference.</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -210,56 +210,56 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">14</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">#' The list containing all the relationships is treated like a map and ignores</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">15</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' entries with `NULL` if they exist.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">16</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">17</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Getter for join_keys ---</pre>
+                      <pre class="language-r">#' @inheritParams base::all.equal</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @param ... further arguments for different methods. Not used with `join_keys`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">19</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk["ds1", "ds2"]</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">20</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @seealso [base::all.equal()]</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">21</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Subsetting join_keys ----</pre>
+                      <pre class="language-r">#' @keywords internal</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -273,4501 +273,1256 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">23</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk["ds1"]</pre>
+                      <pre class="language-r">all.equal.join_keys &lt;- function(target, current, ...) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">24</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">21<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk[1:2]</pre>
+                      <pre class="language-r">  .as_map &lt;- function(.x) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">25</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk[c("ds1", "ds2")]</pre>
+                      <pre class="language-r">    old_attributes &lt;- attributes(.x)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">26</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    # Keep only non-list attributes</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">27</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">`[.join_keys` &lt;- function(x, i, j) {</pre>
+                      <pre class="language-r">    old_attributes[["names"]] &lt;- NULL</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">28</td>
-                    <td class="coverage">35<em>x</em></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (missing(i) &amp;&amp; missing(j)) {</pre>
+                      <pre class="language-r">    old_attributes[["original_class"]] &lt;- old_attributes[["class"]]</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">29</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # because:</pre>
+                      <pre class="language-r">    old_attributes[["class"]] &lt;- NULL</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">30</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # - list(a = 1)[] returns list(a = 1)</pre>
+                      <pre class="language-r">    old_attributes[["parents"]] &lt;- if (!length(old_attributes[["parents"]])) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">31</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">18<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # - data.frame(a = 1)[] returns data.frame(a = 1)</pre>
+                      <pre class="language-r">      list()</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">32</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    return(x)</pre>
+                      <pre class="language-r">    } else {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">33</td>
-                    <td class="coverage">34<em>x</em></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else if (!missing(i) &amp;&amp; is.null(i) || !missing(j) &amp;&amp; is.null(j)) {</pre>
+                      <pre class="language-r">      old_attributes[["parents"]][order(names(old_attributes[["parents"]]))]</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">34</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # because list(a = 1)[NULL] returns NULL</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">35</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # data.frame(a = 1)[NULL, NULL] returns data.frame(</pre>
+                      <pre class="language-r">    attr(.x, "class") &lt;- "list"</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">36</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    return(join_keys())</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">37</td>
-                    <td class="coverage">32<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else if (!missing(i) &amp;&amp; !missing(j)) {</pre>
+                      <pre class="language-r">    # Remove nulls</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">38</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (</pre>
+                      <pre class="language-r">    .x &lt;- Filter(Negate(is.null), .x)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">39</td>
-                    <td class="coverage">8<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      !any(</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">40</td>
-                    <td class="coverage">8<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        checkmate::test_string(i),</pre>
+                      <pre class="language-r">    # Sort named components, preserving positions of unnamed</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">41</td>
-                    <td class="coverage">8<em>x</em></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        checkmate::test_number(i),</pre>
+                      <pre class="language-r">    nx &lt;- rlang::names2(.x)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">42</td>
-                    <td class="coverage">8<em>x</em></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        checkmate::test_logical(i, len = length(x)) &amp;&amp; sum(j) == 1</pre>
+                      <pre class="language-r">    is_named &lt;- nx != ""</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">43</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      ) ||</pre>
+                      <pre class="language-r">    if (any(is_named)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">44</td>
-                    <td class="coverage">8<em>x</em></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        !any(</pre>
+                      <pre class="language-r">      idx &lt;- seq_along(.x)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">45</td>
-                    <td class="coverage">8<em>x</em></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          checkmate::test_string(j),</pre>
+                      <pre class="language-r">      idx[is_named] &lt;- idx[is_named][order(nx[is_named])]</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">46</td>
-                    <td class="coverage">8<em>x</em></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          checkmate::test_number(j),</pre>
+                      <pre class="language-r">      .x &lt;- .x[idx]</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">47</td>
-                    <td class="coverage">8<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          checkmate::test_logical(j, len = length(x)) &amp;&amp; sum(j) == 1</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">48</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        )</pre>
+                      <pre class="language-r">    new_attributes &lt;- if (is.null(attributes(.x))) list() else attributes(.x)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">49</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    ) {</pre>
+                      <pre class="language-r">    attributes(.x) &lt;- utils::modifyList(old_attributes, new_attributes)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">50</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="coverage">42<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      stop(</pre>
+                      <pre class="language-r">    .x</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">51</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        "join_keys[i, j] - Can't extract keys for multiple pairs.",</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">52</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="coverage">21<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        "When specifying a pair [i, j], both indices must point to a single key pair.\n",</pre>
+                      <pre class="language-r">  x &lt;- .as_map(target)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">53</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="coverage">21<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        call. = FALSE</pre>
+                      <pre class="language-r">  y &lt;- .as_map(current)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">54</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">21<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      )</pre>
+                      <pre class="language-r">  all.equal(x, y)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">55</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">56</td>
-                    <td class="coverage">1<em>x</em></td>
+                </tbody>
+              </table>
+            </div>
+            <div id="R/join_keys-parents.R" class="hidden">
+              <table class="table-condensed">
+                <tbody>
+                  <tr class="never">
+                    <td class="num">1</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (is.numeric(i)) i &lt;- names(x)[i]</pre>
+                      <pre class="language-r">#' Get and set parents in `join_keys` object</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">57</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">2</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (is.numeric(j)) j &lt;- names(x)[j]</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">58</td>
+                    <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' `parents()` facilitates the creation of dependencies between datasets by</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">59</td>
-                    <td class="coverage">7<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">4</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    subset_x &lt;- update_keys_given_parents(x[union(i, j)])</pre>
+                      <pre class="language-r">#' assigning a parent-child relationship.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">60</td>
-                    <td class="coverage">7<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">5</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    return(subset_x[[i]][[j]])</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">61</td>
-                    <td class="coverage">24<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">6</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else if (!missing(j)) {</pre>
+                      <pre class="language-r">#' Each element is defined by a `list` element, where `list("child" = "parent")`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">62</td>
+                    <td class="num">7</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # ie. select all keys which have j as dataset_2</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">63</td>
+                    <td class="num">8</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # since list is symmetrical it is equivalent to selecting by i</pre>
+                      <pre class="language-r">#' @param x (`join_keys` or `teal_data`) object that contains "parents" information</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">64</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">9</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    i &lt;- j</pre>
+                      <pre class="language-r">#' to retrieve or manipulate.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">65</td>
+                    <td class="num">10</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">66</td>
+                    <td class="num">11</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @return a `list` of `character` representing the parents.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">67</td>
-                    <td class="coverage">24<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">12</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert(</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">68</td>
-                    <td class="coverage">24<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">13</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    combine = "or",</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">69</td>
-                    <td class="coverage">24<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">14</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    checkmate::check_character(i),</pre>
+                      <pre class="language-r">#' @seealso [join_keys()]</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">70</td>
-                    <td class="coverage">24<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">15</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    checkmate::check_numeric(i),</pre>
+                      <pre class="language-r">parents &lt;- function(x) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">71</td>
-                    <td class="coverage">24<em>x</em></td>
+                    <td class="num">16</td>
+                    <td class="coverage">692<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    checkmate::check_logical(i)</pre>
+                      <pre class="language-r">  UseMethod("parents", x)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">72</td>
+                    <td class="num">17</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">73</td>
+                    <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">74</td>
+                    <td class="num">19</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @describeIn parents Retrieves parents of `join_keys` object.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">75</td>
+                    <td class="num">20</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # Convert integer/logical index to named index</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">76</td>
-                    <td class="coverage">24<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">21</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (checkmate::test_numeric(i) || checkmate::test_logical(i)) {</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">77</td>
-                    <td class="coverage">2<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">22</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    i &lt;- names(x)[i]</pre>
+                      <pre class="language-r">#' # Get parents of join_keys ---</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">78</td>
+                    <td class="num">23</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">79</td>
+                    <td class="num">24</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' jk &lt;- default_cdisc_join_keys["ADEX"]</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">80</td>
+                    <td class="num">25</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # When retrieving a relationship pair, it will also return the symmetric key</pre>
+                      <pre class="language-r">#' parents(jk)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">81</td>
-                    <td class="coverage">24<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">26</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  new_jk &lt;- new_join_keys()</pre>
+                      <pre class="language-r">parents.join_keys &lt;- function(x) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">82</td>
-                    <td class="coverage">24<em>x</em></td>
+                    <td class="num">27</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  queue &lt;- unique(i)</pre>
+                      <pre class="language-r">  if (is.null(attr(x, "parents"))) list() else attr(x, "parents")</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">83</td>
-                    <td class="coverage">24<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">28</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  bin &lt;- character(0)</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">84</td>
+                    <td class="num">29</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">85</td>
+                    <td class="num">30</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # Need to iterate on a mutating queue if subset of a dataset will also</pre>
+                      <pre class="language-r">#' @describeIn parents Retrieves parents of `join_keys` inside `teal_data` object.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">86</td>
+                    <td class="num">31</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  #  select its parent as that parent might have relationships with others</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">87</td>
+                    <td class="num">32</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  #  already selected.</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">88</td>
-                    <td class="coverage">24<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  while (length(queue) &gt; 0) {</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">89</td>
-                    <td class="coverage">53<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">33</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    ix &lt;- queue[1]</pre>
+                      <pre class="language-r">#' # Get parents of join_keys inside teal_data object ---</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">90</td>
-                    <td class="coverage">53<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">34</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    queue &lt;- queue[-1]</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">91</td>
-                    <td class="coverage">53<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">35</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    bin &lt;- c(bin, ix)</pre>
+                      <pre class="language-r">#' td &lt;- teal_data(</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">92</td>
+                    <td class="num">36</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#'   ADSL = rADSL,</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">93</td>
-                    <td class="coverage">53<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">37</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    ix_parent &lt;- parent(x, ix)</pre>
+                      <pre class="language-r">#'   ADTTE = rADTTE,</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">94</td>
+                    <td class="num">38</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#'   ADRS = rADRS,</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">95</td>
-                    <td class="coverage">53<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">39</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (checkmate::test_string(ix_parent, min.chars = 1) &amp;&amp; !ix_parent %in% c(queue, bin)) {</pre>
+                      <pre class="language-r">#'   join_keys = default_cdisc_join_keys[c("ADSL", "ADTTE", "ADRS")]</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">96</td>
-                    <td class="coverage">10<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">40</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      queue &lt;- c(queue, ix_parent)</pre>
+                      <pre class="language-r">#' )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">97</td>
+                    <td class="num">41</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#' parents(td)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">98</td>
+                    <td class="num">42</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">parents.teal_data &lt;- function(x) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">99</td>
-                    <td class="coverage">53<em>x</em></td>
+                    <td class="num">43</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    ix_valid_names &lt;- names(x[[ix]]) %in% c(queue, bin)</pre>
+                      <pre class="language-r">  parents(x@join_keys)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">100</td>
+                    <td class="num">44</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">101</td>
-                    <td class="coverage">53<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    new_jk[[ix]] &lt;- x[[ix]][ix_valid_names]</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">102</td>
+                    <td class="num">45</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">103</td>
+                    <td class="num">46</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # Add primary key of parent</pre>
+                      <pre class="language-r">#' @describeIn parents Assignment of parents in `join_keys` object.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">104</td>
-                    <td class="coverage">53<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">47</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (length(ix_parent) &gt; 0) {</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">105</td>
-                    <td class="coverage">20<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">48</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      new_jk[[ix_parent]][[ix_parent]] &lt;- x[[ix_parent]][[ix_parent]]</pre>
+                      <pre class="language-r">#' @param value (`named list`) of `character` vectors.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">106</td>
+                    <td class="num">49</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">107</td>
+                    <td class="num">50</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">108</td>
+                    <td class="num">51</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">109</td>
-                    <td class="coverage">24<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  common_parents_ix &lt;- names(parents(x)) %in% names(new_jk) &amp;</pre>
+                      <pre class="language-r">`parents&lt;-` &lt;- function(x, value) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">110</td>
-                    <td class="coverage">24<em>x</em></td>
+                    <td class="num">52</td>
+                    <td class="coverage">438<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    parents(x) %in% names(new_jk)</pre>
+                      <pre class="language-r">  UseMethod("parents&lt;-", x)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">111</td>
+                    <td class="num">53</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">112</td>
-                    <td class="coverage">13<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (any(common_parents_ix)) parents(new_jk) &lt;- parents(x)[common_parents_ix]</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">113</td>
+                    <td class="num">54</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">114</td>
-                    <td class="coverage">24<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  new_jk</pre>
-                    </td>
-                  </tr>
                   <tr class="never">
-                    <td class="num">115</td>
+                    <td class="num">55</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#' @describeIn parents Assignment of parents of `join_keys` object.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">116</td>
+                    <td class="num">56</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">117</td>
+                    <td class="num">57</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname join_keys</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">118</td>
+                    <td class="num">58</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @order 2</pre>
+                      <pre class="language-r">#' # Assignment of parents ---</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">119</td>
+                    <td class="num">59</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">120</td>
+                    <td class="num">60</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param directed (`logical(1)`) Flag that indicates whether it should create</pre>
+                      <pre class="language-r">#' jk &lt;- join_keys(</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">121</td>
+                    <td class="num">61</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' a parent-child relationship between the datasets.</pre>
+                      <pre class="language-r">#'   join_key("ds1", "ds2", "id"),</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">122</td>
+                    <td class="num">62</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  - `TRUE` (default) `dataset_1` is the parent of `dataset_2`;</pre>
+                      <pre class="language-r">#'   join_key("ds5", "ds6", "id"),</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">123</td>
+                    <td class="num">63</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  - `FALSE` when the relationship is undirected.</pre>
+                      <pre class="language-r">#'   join_key("ds7", "ds6", "id")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">124</td>
+                    <td class="num">64</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @section Functions:</pre>
+                      <pre class="language-r">#' )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">125</td>
+                    <td class="num">65</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - `x[i, j] &lt;- value`: Assignment of a key to pair `(i, j)`.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">126</td>
+                    <td class="num">66</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - `x[i] &lt;- value`: This (without `j` parameter) **is not** a supported</pre>
+                      <pre class="language-r">#' parents(jk) &lt;- list(ds2 = "ds1")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">127</td>
+                    <td class="num">67</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' operation for `join_keys`.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">128</td>
+                    <td class="num">68</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - `join_keys(x)[i, j] &lt;- value`: Assignment to `join_keys` object stored in `x`,</pre>
+                      <pre class="language-r">#' # Setting individual parent-child relationship</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">129</td>
+                    <td class="num">69</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' such as a `teal_data` object or `join_keys` object itself.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">130</td>
+                    <td class="num">70</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' parents(jk)["ds6"] &lt;- "ds5"</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">131</td>
+                    <td class="num">71</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">#' parents(jk)["ds7"] &lt;- "ds6"</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">132</td>
+                    <td class="num">72</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">`parents&lt;-.join_keys` &lt;- function(x, value) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">133</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">73</td>
+                    <td class="coverage">437<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Setting a new primary key ---</pre>
+                      <pre class="language-r">  checkmate::assert_list(value, types = "character", names = "named")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">134</td>
+                    <td class="num">74</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">135</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">75</td>
+                    <td class="coverage">434<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk["ds4", "ds4"] &lt;- "pk4"</pre>
+                      <pre class="language-r">  new_parents &lt;- list()</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">136</td>
+                    <td class="num">76</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk["ds5", "ds5"] &lt;- "pk5"</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">137</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">77</td>
+                    <td class="coverage">434<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  for (dataset in names(value)) {</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">138</td>
+                    <td class="num">78</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Setting a single relationship pair ---</pre>
+                      <pre class="language-r">    # Custom .var.name so it is verbose and helpful for users</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">139</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">79</td>
+                    <td class="coverage">168<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    checkmate::assert_string(value[[dataset]], .var.name = sprintf("value[[\"%s\"]]", dataset))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">140</td>
+                    <td class="num">80</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk["ds1", "ds4"] &lt;- c("pk1" = "pk4")</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">141</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">81</td>
+                    <td class="coverage">167<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    parent &lt;- new_parents[[dataset]]</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">142</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">82</td>
+                    <td class="coverage">167<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Removing a key ---</pre>
+                      <pre class="language-r">    checkmate::assert(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">143</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">83</td>
+                    <td class="coverage">167<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      checkmate::check_null(parent),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">144</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">84</td>
+                    <td class="coverage">167<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk["ds5", "ds5"] &lt;- NULL</pre>
+                      <pre class="language-r">      checkmate::check_true(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">145</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">85</td>
+                    <td class="coverage">167<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">`[&lt;-.join_keys` &lt;- function(x, i, j, directed = TRUE, value) {</pre>
+                      <pre class="language-r">        length(parent) == 0 &amp;&amp;</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">146</td>
-                    <td class="coverage">11<em>x</em></td>
+                    <td class="num">86</td>
+                    <td class="coverage">167<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_flag(directed)</pre>
+                      <pre class="language-r">          length(value[[dataset]]) == 0</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">147</td>
-                    <td class="coverage">11<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">87</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (missing(i) || missing(j)) {</pre>
+                      <pre class="language-r">      ),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">148</td>
-                    <td class="coverage">4<em>x</em></td>
+                    <td class="num">88</td>
+                    <td class="coverage">167<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    stop("join_keys[i, j] specify both indices to set a key pair.")</pre>
+                      <pre class="language-r">      checkmate::check_true(parent == value[[dataset]]),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">149</td>
-                    <td class="coverage">7<em>x</em></td>
+                    <td class="num">89</td>
+                    <td class="coverage">167<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else if (!missing(i) &amp;&amp; is.null(i) || !missing(j) &amp;&amp; is.null(j)) {</pre>
+                      <pre class="language-r">      "Please check the difference between provided datasets parents and provided join_keys parents.",</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">150</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="num">90</td>
+                    <td class="coverage">167<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    stop("join_keys[i, j] neither i nor j can be NULL.")</pre>
+                      <pre class="language-r">      .var.name = "value"</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">151</td>
+                    <td class="num">91</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else if (</pre>
+                      <pre class="language-r">    )</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">152</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="num">92</td>
+                    <td class="coverage">167<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    !any(</pre>
+                      <pre class="language-r">    if (is.null(parent)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">153</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="num">93</td>
+                    <td class="coverage">167<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      checkmate::test_string(i),</pre>
+                      <pre class="language-r">      new_parents[[dataset]] &lt;- value[[dataset]]</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">154</td>
-                    <td class="coverage">5<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">94</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      checkmate::test_number(i),</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">155</td>
-                    <td class="coverage">5<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">95</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      checkmate::test_logical(i, len = length(x)) &amp;&amp; sum(j) == 1</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">156</td>
+                    <td class="num">96</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    ) ||</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">157</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="num">97</td>
+                    <td class="coverage">433<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      !any(</pre>
+                      <pre class="language-r">  if (is_dag(new_parents)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">158</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="num">98</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        checkmate::test_string(j),</pre>
+                      <pre class="language-r">    stop("Cycle detected in a parent and child dataset graph.")</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">159</td>
-                    <td class="coverage">5<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">99</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        checkmate::test_number(j),</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">160</td>
-                    <td class="coverage">5<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">100</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        checkmate::test_logical(j, len = length(x)) &amp;&amp; sum(j) == 1</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">161</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">101</td>
+                    <td class="coverage">429<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      )</pre>
+                      <pre class="language-r">  attr(x, "parents") &lt;- new_parents</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">162</td>
+                    <td class="num">102</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  ) {</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">163</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="num">103</td>
+                    <td class="coverage">429<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    stop(</pre>
+                      <pre class="language-r">  assert_parent_child(x)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">164</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="num">104</td>
+                    <td class="coverage">428<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      "join_keys[i, j] &lt;- Can't set keys to specified indices.\n",</pre>
+                      <pre class="language-r">  x</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">165</td>
-                    <td class="coverage">2<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">105</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      "When setting pair [i, j], both indices must point to a single key pair.\n",</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">166</td>
-                    <td class="coverage">2<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">106</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      call. = FALSE</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">167</td>
+                    <td class="num">107</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    )</pre>
+                      <pre class="language-r">#' @describeIn parents Assignment of parents of `join_keys` inside `teal_data` object.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">168</td>
+                    <td class="num">108</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">169</td>
+                    <td class="num">109</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">170</td>
+                    <td class="num">110</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # Handle join key removal separately</pre>
+                      <pre class="language-r">#' # Assignment of parents of join_keys inside teal_data object ---</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">171</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">111</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (is.null(value)) {</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">172</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">112</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    x[[i]][[j]] &lt;- NULL</pre>
+                      <pre class="language-r">#' parents(td) &lt;- list("ADTTE" = "ADSL") # replace existing</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">173</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">113</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    return(x)</pre>
+                      <pre class="language-r">#' parents(td)["ADRS"] &lt;- "ADSL" # add new parent</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">174</td>
+                    <td class="num">114</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">`parents&lt;-.teal_data` &lt;- function(x, value) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">175</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">115</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">  parents(x@join_keys) &lt;- value</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">176</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="num">116</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  c(x, join_key(i, j, value, directed))</pre>
+                      <pre class="language-r">  x</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">177</td>
+                    <td class="num">117</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">178</td>
+                    <td class="num">118</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">179</td>
+                    <td class="num">119</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname join_keys</pre>
+                      <pre class="language-r">#' @describeIn parents Getter for individual parent.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">180</td>
+                    <td class="num">120</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">181</td>
+                    <td class="num">121</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @order 1000</pre>
+                      <pre class="language-r">#' @param dataset_name (`character(1)`) Name of dataset to query on their parent.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">182</td>
+                    <td class="num">122</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @usage ## Preferred method is x[i, j] &lt;- value</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">183</td>
+                    <td class="num">123</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' x[[i]][[j]] &lt;- value</pre>
+                      <pre class="language-r">#' @return For `parent(x, dataset_name)` returns `NULL` if parent does not exist.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">184</td>
+                    <td class="num">124</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">185</td>
+                    <td class="num">125</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @section Functions:</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">186</td>
+                    <td class="num">126</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - `x[[i]][[j]] &lt;- value`: It is equivalent as  `x[i, j] &lt;- value`.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">187</td>
+                    <td class="num">127</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">188</td>
+                    <td class="num">128</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">#' # Get individual parent ---</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">189</td>
+                    <td class="num">129</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">190</td>
+                    <td class="num">130</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Setting via x[[i]] &lt;- value ---</pre>
+                      <pre class="language-r">#' parent(jk, "ds2")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">191</td>
+                    <td class="num">131</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' parent(td, "ADTTE")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">192</td>
+                    <td class="num">132</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk &lt;- join_keys()</pre>
+                      <pre class="language-r">parent &lt;- function(x, dataset_name) {</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">133</td>
+                    <td class="coverage">169<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  checkmate::assert_string(dataset_name)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">193</td>
+                    <td class="num">134</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk[["ds6"]][["ds6"]] &lt;- "pk6"</pre>
+                      <pre class="language-r">  # assert x is performed by parents()</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">135</td>
+                    <td class="coverage">169<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  parents(x)[[dataset_name]]</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">194</td>
+                    <td class="num">136</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk[["ds7"]] &lt;- list(ds7 = "pk7", ds6 = c(pk7 = "pk6"))</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
+                </tbody>
+              </table>
+            </div>
+            <div id="R/deprecated.R" class="hidden">
+              <table class="table-condensed">
+                <tbody>
                   <tr class="never">
-                    <td class="num">195</td>
+                    <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk[["ds7"]][["ds7"]] &lt;- NULL # removes key</pre>
+                      <pre class="language-r">#' Deprecated `TealData` class and related functions</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">196</td>
+                    <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">197</td>
+                    <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk</pre>
+                      <pre class="language-r">#' @description</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">198</td>
+                    <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' `r lifecycle::badge("deprecated")`</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">199</td>
+                    <td class="num">5</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">200</td>
+                    <td class="num">6</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">`[[&lt;-.join_keys` &lt;- function(x, i, value) {</pre>
+                      <pre class="language-r">#' The `TealData` class and associated functions have been deprecated. Use [teal_data()] instead.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">201</td>
-                    <td class="coverage">397<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">7</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert(</pre>
+                      <pre class="language-r">#' See the [Migration guide](https://github.com/insightsengineering/teal/discussions/945) for details.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">202</td>
-                    <td class="coverage">397<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">8</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    combine = "or",</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">203</td>
-                    <td class="coverage">397<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    checkmate::check_string(i),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">204</td>
-                    <td class="coverage">397<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    checkmate::check_number(i),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">205</td>
-                    <td class="coverage">397<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    checkmate::check_logical(i, len = length(x))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">206</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">207</td>
-                    <td class="coverage">397<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_list(value, names = "named", types = "character", null.ok = TRUE)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">208</td>
-                    <td class="coverage">390<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (checkmate::test_numeric(i) || checkmate::test_logical(i)) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">209</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    i &lt;- names(x)[[i]]</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">210</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">211</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">212</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  # Normalize values</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">213</td>
-                    <td class="coverage">390<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  norm_value &lt;- lapply(seq_along(value), function(.x) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">214</td>
-                    <td class="coverage">551<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    join_key(i, names(value)[.x], value[[.x]])</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">215</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  })</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">216</td>
-                    <td class="coverage">390<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  names(norm_value) &lt;- names(value)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">217</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">218</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  # Check if multiple modifications don't have a conflict</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">219</td>
-                    <td class="coverage">390<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  repeated_value_ix &lt;- names(value) %in% names(value)[duplicated(names(value))]</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">220</td>
-                    <td class="coverage">390<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  repeated &lt;- norm_value[repeated_value_ix]</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">221</td>
-                    <td class="coverage">390<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  vapply(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">222</td>
-                    <td class="coverage">390<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    seq_along(repeated),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">223</td>
-                    <td class="coverage">390<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    function(.ix, .x_value = repeated[[.ix]], .x_name = names(.x_value[[1]])) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">224</td>
-                    <td class="coverage">3<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      assert_compatible_keys2(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">225</td>
-                    <td class="coverage">3<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        .x_value,</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">226</td>
-                    <td class="coverage">3<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        unlist(unname(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">227</td>
-                    <td class="coverage">3<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">          repeated[-.ix][names(repeated[-.ix]) == .x_name]</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">228</td>
-                    <td class="coverage">3<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        ), recursive = FALSE)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">229</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">230</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    },</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">231</td>
-                    <td class="coverage">390<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    logical(1)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">232</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">233</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">234</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  norm_value &lt;- lapply(norm_value, function(x) x[[1]][[1]])</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">235</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  names(norm_value) &lt;- names(value)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">236</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">237</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  # Safe to do as duplicated are the same</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">238</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  norm_value[duplicated(names(norm_value))] &lt;- NULL</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">239</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">240</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  # Keep only elements with length &gt; 0L</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">241</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  norm_value &lt;- Filter(length, norm_value)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">242</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">243</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  # Remove classes to use list-based get/assign operations</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">244</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  new_x &lt;- unclass(x)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">245</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">246</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  # In case a pair is removed, also remove the symmetric pair and update parents</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">247</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  removed_names &lt;- setdiff(names(new_x[[i]]), names(norm_value))</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">248</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  for (.x in removed_names) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">249</td>
-                    <td class="coverage">2<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    if (identical(parent(x, .x), i)) attr(new_x, "parents")[[.x]] &lt;- NULL</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">250</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    if (identical(parent(x, i), .x)) attr(new_x, "parents")[[i]] &lt;- NULL</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">251</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">252</td>
-                    <td class="coverage">5<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    new_x[[.x]][[i]] &lt;- NULL</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">253</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">254</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">255</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  new_x[[i]] &lt;- norm_value</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">256</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">257</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  # Iterate on all new values to create symmetrical pair</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">258</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  for (ds2 in names(norm_value)) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">259</td>
-                    <td class="coverage">310<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    if (ds2 == i) next</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">260</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">261</td>
-                    <td class="coverage">237<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    keep_value &lt;- if (is.null(x)) list() else new_x[[ds2]]</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">262</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">263</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    # Invert key</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">264</td>
-                    <td class="coverage">237<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    new_value &lt;- stats::setNames(names(norm_value[[ds2]]), norm_value[[ds2]])</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">265</td>
-                    <td class="coverage">237<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    keep_value[[i]] &lt;- new_value</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">266</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">267</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    # Assign symmetrical</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">268</td>
-                    <td class="coverage">237<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    new_x[[ds2]] &lt;- keep_value</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">269</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">270</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">271</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  preserve_attr &lt;- attributes(new_x)[!names(attributes(new_x)) %in% "names"]</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">272</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  # Remove NULL or empty keys</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">273</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  new_x &lt;- Filter(function(x) length(x) != 0L, new_x)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">274</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  attributes(new_x) &lt;- utils::modifyList(attributes(new_x), preserve_attr)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">275</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">276</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  #</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">277</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  # restore class</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">278</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  class(new_x) &lt;- class(x)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">279</td>
-                    <td class="coverage">389<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  new_x</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">280</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
-                    </td>
-                  </tr>
-                </tbody>
-              </table>
-            </div>
-            <div id="R/teal_data.R" class="hidden">
-              <table class="table-condensed">
-                <tbody>
-                  <tr class="never">
-                    <td class="num">1</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' Comprehensive data integration function for `teal` applications</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">2</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">3</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @description</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">4</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' `r lifecycle::badge("stable")`</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">5</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">6</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' Universal function to pass data to teal application.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">7</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">8</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @param ... any number of objects (presumably data objects) provided as `name = value` pairs.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">9</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">10</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @param join_keys (`join_keys` or single `join_key_set`)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">11</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' optional object with datasets column names used for joining.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">12</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' If empty then no joins between pairs of objects.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">13</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">14</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @param code (`character`, `language`) optional code to reproduce the datasets provided in `...`.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">15</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  Note this code is not executed and the `teal_data` may not be reproducible</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">16</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">17</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @param check (`logical`) `r lifecycle::badge("deprecated")`</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">18</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  Use [verify()] to verify code reproducibility .</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">19</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">20</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @return A `teal_data` object.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">21</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">22</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">23</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">24</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">25</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' teal_data(x1 = iris, x2 = mtcars)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">26</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">27</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">teal_data &lt;- function(...,</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">28</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">                      join_keys = teal.data::join_keys(),</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">29</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">                      code = character(0),</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">30</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">                      check) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">31</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  data_objects &lt;- rlang::list2(...)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">32</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (inherits(join_keys, "join_key_set")) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">33</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    join_keys &lt;- teal.data::join_keys(join_keys)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">34</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">35</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (!missing(check)) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">36</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    lifecycle::deprecate_stop(</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">37</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      when = "0.4.0",</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">38</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      "teal_data(</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">39</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        check = 'check argument is deprecated. Use `verify()` to verify code reproducibility.</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">40</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        Find more information on https://github.com/insightsengineering/teal/discussions/945'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">41</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      )"</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">42</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">43</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">44</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">45</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">46</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    checkmate::test_list(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">47</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      data_objects,</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">48</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      types = c("TealDataConnector", "TealDataset", "TealDatasetConnector"),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">49</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      min.len = 1</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">50</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">51</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  ) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">52</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    lifecycle::deprecate_stop(</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">53</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      when = "0.4.0",</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">54</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      "teal_data(</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">55</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        data_objects = 'should use data directly. Using TealDatasetConnector and TealDataset is deprecated.</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">56</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        Find more information on https://github.com/insightsengineering/teal/discussions/945'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">57</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      )"</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">58</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">59</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  } else {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">60</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    if (length(data_objects) &gt; 0 &amp;&amp; !checkmate::test_names(names(data_objects), type = "named")) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">61</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      stop("Dot (`...`) arguments on `teal_data()` must be named.")</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">62</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">63</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    new_teal_data(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">64</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      data = data_objects,</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">65</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      code = code,</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">66</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      join_keys = join_keys</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">67</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">68</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">69</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
-                    </td>
-                  </tr>
-                </tbody>
-              </table>
-            </div>
-            <div id="R/join_key.R" class="hidden">
-              <table class="table-condensed">
-                <tbody>
-                  <tr class="never">
-                    <td class="num">1</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' Create a relationship between a pair of datasets</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">2</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">3</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @description</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">4</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' `r lifecycle::badge("stable")`</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">5</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">6</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' Create a relationship between two datasets, `dataset_1` and `dataset_2`.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">7</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' By default, this function establishes a directed relationship with `dataset_1` as the parent.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">8</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' If `dataset_2` is not specified, the function creates a primary key for `dataset_1`.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">9</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">10</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @param dataset_1,dataset_2 (`character(1)`) Dataset names. When `dataset_2` is omitted,</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">11</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' a primary key for `dataset_1` is created.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">12</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @param keys (optionally named `character`) Column mapping between the datasets,</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">13</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' where `names(keys)` maps columns in `dataset_1` corresponding to columns of</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">14</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' `dataset_2` given by the elements of `keys`.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">15</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' - If unnamed, the same column names are used for both datasets.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">16</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' - If any element of the `keys` vector is empty with a non-empty name, then the name is</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">17</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' used for both datasets.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">18</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @param directed (`logical(1)`) Flag that indicates whether it should create</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">19</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' a parent-child relationship between the datasets.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">20</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  - `TRUE` (default) `dataset_1` is the parent of `dataset_2`;</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">21</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  - `FALSE` when the relationship is undirected.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">22</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">23</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @return object of class `join_key_set` to be passed into `join_keys` function.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">24</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">25</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">26</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' join_key("d1", "d2", c("A"))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">27</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' join_key("d1", "d2", c("A" = "B"))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">28</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' join_key("d1", "d2", c("A" = "B", "C"))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">29</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">30</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">31</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @seealso [join_keys()], [parents()]</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">32</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">33</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">join_key &lt;- function(dataset_1, dataset_2 = dataset_1, keys, directed = TRUE) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">34</td>
-                    <td class="coverage">1103<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_string(dataset_1)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">35</td>
-                    <td class="coverage">1103<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_string(dataset_2)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">36</td>
-                    <td class="coverage">1100<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_character(keys, any.missing = FALSE)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">37</td>
-                    <td class="coverage">1095<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_flag(directed)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">38</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">39</td>
-                    <td class="coverage">1095<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (length(keys) &gt; 0) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">40</td>
-                    <td class="coverage">1093<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    if (is.null(names(keys))) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">41</td>
-                    <td class="coverage">526<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      names(keys) &lt;- keys</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">42</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">43</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">44</td>
-                    <td class="coverage">1093<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    keys &lt;- trimws(keys)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">45</td>
-                    <td class="coverage">1093<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    names(keys) &lt;- trimws(names(keys))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">46</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">47</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    # Remove keys with empty value and without name</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">48</td>
-                    <td class="coverage">1093<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    if (any(keys == "" &amp; names(keys) == "")) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">49</td>
-                    <td class="coverage">6<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      message("Key with an empty value and name are ignored.")</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">50</td>
-                    <td class="coverage">6<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      keys &lt;- keys[keys != "" &amp; names(keys) != ""]</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">51</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">52</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">53</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    # Set name of keys without one: c("A") -&gt; c("A" = "A")</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">54</td>
-                    <td class="coverage">1093<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    if (any(names(keys) == "")) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">55</td>
-                    <td class="coverage">4<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      names(keys)[names(keys) == ""] &lt;- keys[names(keys) == ""]</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">56</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">57</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">58</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    # Set value of keys with empty string, but non-empty name: c("A" = "") -&gt; c("A" = "A")</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">59</td>
-                    <td class="coverage">1093<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    if (any(keys == "")) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">60</td>
-                    <td class="coverage">4<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      keys[keys == ""] &lt;- names(keys[keys == ""])</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">61</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">62</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">63</td>
-                    <td class="coverage">1093<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    stopifnot(!is.null(names(keys)))</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">64</td>
-                    <td class="coverage">1093<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    stopifnot(!anyDuplicated(keys))</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">65</td>
-                    <td class="coverage">1092<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    stopifnot(!anyDuplicated(names(keys)))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">66</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">67</td>
-                    <td class="coverage">1091<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    if (dataset_1 == dataset_2 &amp;&amp; any(names(keys) != keys)) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">68</td>
-                    <td class="coverage">2<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      stop("Keys within a dataset must match exactly: keys = c('A' = 'B') are not allowed")</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">69</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">70</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  } else {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">71</td>
-                    <td class="coverage">2<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    keys &lt;- NULL</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">72</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">73</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">74</td>
-                    <td class="coverage">1091<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  parents &lt;- if (directed &amp;&amp; dataset_1 != dataset_2) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">75</td>
-                    <td class="coverage">413<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    stats::setNames(list(dataset_1), dataset_2)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">76</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  } else {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">77</td>
-                    <td class="coverage">678<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    list()</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">78</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">79</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">80</td>
-                    <td class="coverage">1091<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  structure(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">81</td>
-                    <td class="coverage">1091<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    list(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">82</td>
-                    <td class="coverage">1091<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      structure(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">83</td>
-                    <td class="coverage">1091<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        list(keys),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">84</td>
-                    <td class="coverage">1091<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        names = dataset_2</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">85</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">86</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    ),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">87</td>
-                    <td class="coverage">1091<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    names = dataset_1,</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">88</td>
-                    <td class="coverage">1091<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    class = "join_key_set",</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">89</td>
-                    <td class="coverage">1091<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    parents = parents</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">90</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">91</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
-                    </td>
-                  </tr>
-                </tbody>
-              </table>
-            </div>
-            <div id="R/teal_data-class.R" class="hidden">
-              <table class="table-condensed">
-                <tbody>
-                  <tr class="never">
-                    <td class="num">1</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">setOldClass("join_keys")</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">2</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">3</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' Reproducible data</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">4</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">5</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' Reproducible data container class. Inherits code tracking behavior from [`teal.code::qenv-class`].</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">6</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">7</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' This class provides an isolated environment in which to store and process data with all code being recorded.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">8</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' The environment, code, data set names, and data joining keys are stored in their respective slots.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">9</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' These slots should never be accessed directly, use the provided get/set functions.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">10</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">11</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' As code is evaluated in `teal_data`, messages and warnings are stored in their respective slots.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">12</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' If errors are raised, a `qenv.error` object is returned.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">13</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">14</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @name teal_data-class</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">15</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname teal_data-class</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">16</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">17</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @slot env (`environment`) environment containing data sets and possibly auxiliary variables.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">18</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  Access variables with [get_var()] or [`[[`].</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">19</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  No setter provided. Evaluate code to add variables into `@env`.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">20</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @slot code (`character`) vector representing code necessary to reproduce the contents of `@env`.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">21</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  Access with [get_code()].</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">22</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  No setter provided. Evaluate code to append code to the slot.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">23</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @slot id (`integer`) random identifier assigned to each element of `@code`. Used internally.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">24</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @slot warnings (`character`) vector of warnings raised when evaluating code.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">25</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  Access with [get_warnings()].</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">26</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @slot messages (`character`) vector of messages raised when evaluating code.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">27</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @slot join_keys (`join_keys`) object specifying joining keys for data sets in `@env`.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">28</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  Access or modify with [join_keys()].</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">29</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @slot datanames (`character`) vector of names of data sets in `@env`.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">30</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  Used internally to distinguish them from auxiliary variables.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">31</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  Access or modify with [datanames()].</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">32</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @slot verified (`logical(1)`) flag signifying that code in `@code` has been proven to yield contents of `@env`.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">33</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'  Used internally. See [`verify()`] for more details.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">34</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">35</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @import teal.code</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">36</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">37</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">setClass(</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">38</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  Class = "teal_data",</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">39</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  contains = "qenv",</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">40</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  slots = c(join_keys = "join_keys", datanames = "character", verified = "logical"),</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">41</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  prototype = list(</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">42</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    join_keys = join_keys(),</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">43</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    datanames = character(0),</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">44</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    verified = logical(0)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">45</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">46</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">47</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">48</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' Initialize `teal_data` object</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">49</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">50</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @name new_teal_data</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">51</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">52</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @param data (`named list`) of data objects.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">53</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @param code (`character` or `language`) code to reproduce the `data`.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">54</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'   Accepts and stores comments also.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">55</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @param join_keys (`join_keys`) object</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">56</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @param datanames (`character`) names of datasets passed to `data`.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">57</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'   Needed when non-dataset objects are needed in the `env` slot.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">58</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname new_teal_data</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">59</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">60</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">new_teal_data &lt;- function(data,</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">61</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">                          code = character(0),</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">62</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">                          join_keys = join_keys(),</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">63</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">                          datanames = names(data)) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">64</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_list(data)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">65</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_class(join_keys, "join_keys")</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">66</td>
-                    <td class="coverage">64<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (is.null(datanames)) datanames &lt;- character(0) # todo: allow to specify</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">67</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_character(datanames)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">68</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (!any(is.language(code), is.character(code))) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">69</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    stop("`code` must be a character or language object.")</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">70</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">71</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">72</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (is.language(code)) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">73</td>
-                    <td class="coverage">2<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    code &lt;- paste(lang2calls(code), collapse = "\n")</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">74</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">75</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (length(code)) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">76</td>
-                    <td class="coverage">14<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    code &lt;- paste(code, collapse = "\n")</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">77</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">78</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  verified &lt;- (length(code) == 0L &amp;&amp; length(data) == 0L)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">79</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">80</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  id &lt;- sample.int(.Machine$integer.max, size = length(code))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">81</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">82</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  new_env &lt;- rlang::env_clone(list2env(data), parent = parent.env(.GlobalEnv))</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">83</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  lockEnvironment(new_env, bindings = TRUE)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">84</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">85</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  datanames &lt;- .get_sorted_datanames(datanames = datanames, join_keys = join_keys, env = new_env)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">86</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">87</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  methods::new(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">88</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    "teal_data",</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">89</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    env = new_env,</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">90</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    code = code,</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">91</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    warnings = rep("", length(code)),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">92</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    messages = rep("", length(code)),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">93</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    id = id,</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">94</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    join_keys = join_keys,</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">95</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    datanames = datanames,</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">96</td>
-                    <td class="coverage">97<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    verified = verified</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">97</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">98</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
-                    </td>
-                  </tr>
-                </tbody>
-              </table>
-            </div>
-            <div id="R/verify.R" class="hidden">
-              <table class="table-condensed">
-                <tbody>
-                  <tr class="never">
-                    <td class="num">1</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' Verify code reproducibility</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">2</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">3</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' Checks whether code in `teal_data` object reproduces the stored objects.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">4</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">5</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' If objects created by code in the `@code` slot of `x` are `all_equal` to the contents of the `@env` slot,</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">6</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' the function updates the `@verified` slot to `TRUE` in the returned `teal_data` object.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">7</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' Once verified, the slot will always be set to `TRUE`.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">8</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' If the `@code` fails to recreate objects in `teal_data@env`, an error is raised.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">9</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">10</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @return Input `teal_data` object or error.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">11</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">12</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @param x `teal_data` object</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">13</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">14</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' tdata1 &lt;- teal_data()</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">15</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' tdata1 &lt;- within(tdata1, {</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">16</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'   a &lt;- 1</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">17</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'   b &lt;- a^5</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">18</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'   c &lt;- list(x = 2)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">19</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' })</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">20</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' verify(tdata1)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">21</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">22</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' tdata2 &lt;- teal_data(x1 = iris, code = "x1 &lt;- iris")</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">23</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' verify(tdata2)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">24</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' verify(tdata2)@verified</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">25</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' tdata2@verified</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">26</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">27</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' tdata3 &lt;- teal_data()</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">28</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' tdata3 &lt;- within(tdata3, {</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">29</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'   stop("error")</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">30</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' })</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">31</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' try(verify(tdata3)) # fails</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">32</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">33</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">34</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' a &lt;- 1</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">35</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' b &lt;- a + 2</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">36</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' c &lt;- list(x = 2)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">37</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' d &lt;- 5</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">38</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' tdata4 &lt;- teal_data(</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">39</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'   a = a, b = b, c = c, d = d,</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">40</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'   code = "a &lt;- 1</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">41</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'           b &lt;- a</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">42</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'           c &lt;- list(x = 2)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">43</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'           e &lt;- 1"</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">44</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">45</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' tdata4</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">46</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' \dontrun{</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">47</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' verify(tdata4) # fails</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">48</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">49</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">50</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @name verify</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">51</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname verify</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">52</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @aliases verify,teal_data-method</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">53</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @aliases verify,qenv.error-method</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">54</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">55</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">56</td>
-                    <td class="coverage">5<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">setGeneric("verify", function(x) standardGeneric("verify"))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">57</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">setMethod("verify", signature = "teal_data", definition = function(x) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">58</td>
-                    <td class="coverage">4<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (x@verified) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">59</td>
-                    <td class="coverage">2<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    return(x)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">60</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">61</td>
-                    <td class="coverage">2<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  x_name &lt;- deparse(substitute(x))</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">62</td>
-                    <td class="coverage">2<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  y &lt;- eval_code(teal_data(), get_code(x))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">63</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">64</td>
-                    <td class="coverage">2<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (inherits(y, "qenv.error")) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">65</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    stop(conditionMessage(y), call. = FALSE)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">66</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">67</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">68</td>
-                    <td class="coverage">2<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  reproduced &lt;- isTRUE(all.equal(x@env, y@env))</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">69</td>
-                    <td class="coverage">2<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (reproduced) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">70</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    x@verified &lt;- TRUE</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">71</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    methods::validObject(x)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">72</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    x</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">73</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  } else {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">74</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    error &lt;- "Code verification failed."</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">75</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">76</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    objects_diff &lt;- vapply(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">77</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      intersect(names(x@env), names(y@env)),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">78</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      function(element) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">79</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        isTRUE(all.equal(x@env[[element]], y@env[[element]]))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">80</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      },</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">81</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      logical(1)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">82</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">83</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">84</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    names_diff_other &lt;- setdiff(names(y@env), names(x@env))</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">85</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    names_diff_inenv &lt;- setdiff(names(x@env), names(y@env))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">86</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">87</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    if (length(objects_diff)) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">88</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      error &lt;- c(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">89</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        error,</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">90</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        paste0("Object(s) recreated with code that have different structure in ", x_name, ":"),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">91</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        paste0("  \u2022 ", names(which(!objects_diff)))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">92</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">93</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">94</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    if (length(names_diff_inenv)) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">95</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      error &lt;- c(</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">96</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        error,</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">97</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        paste0("Object(s) not created with code that exist in ", x_name, ":"),</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">98</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        paste0("  \u2022 ", names_diff_inenv)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">99</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">100</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">101</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    if (length(names_diff_other)) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">102</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      error &lt;- c(</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">103</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        error,</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">104</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        paste0("Object(s) created with code that do not exist in ", x_name, ":"),</pre>
-                    </td>
-                  </tr>
-                  <tr class="missed">
-                    <td class="num">105</td>
-                    <td class="coverage">!</td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        paste0("  \u2022 ", names_diff_other)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">106</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      )</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">107</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">108</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">109</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    stop(paste(error, collapse = "\n"), call. = FALSE)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">110</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">111</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">})</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">112</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">setMethod("verify", signature = "qenv.error", definition = function(x) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">113</td>
-                    <td class="coverage">1<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  stop(conditionMessage(x), call. = FALSE)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">114</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">})</pre>
-                    </td>
-                  </tr>
-                </tbody>
-              </table>
-            </div>
-            <div id="R/deprecated.R" class="hidden">
-              <table class="table-condensed">
-                <tbody>
-                  <tr class="never">
-                    <td class="num">1</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' Deprecated `TealData` class and related functions</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">2</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">3</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' @description</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">4</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' `r lifecycle::badge("deprecated")`</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">5</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">6</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' The `TealData` class and associated functions have been deprecated. Use [teal_data()] instead.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">7</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' See the [Migration guide](https://github.com/insightsengineering/teal/discussions/945) for details.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">8</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">9</td>
-                    <td class="coverage"></td>
+                  <tr class="never">
+                    <td class="num">9</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#' @name TealData</pre>
                     </td>
@@ -7127,105 +3882,105 @@ <h2>teal.data coverage - 89.08%</h2>
                 </tbody>
               </table>
             </div>
-            <div id="R/formatters_var_labels.R" class="hidden">
+            <div id="R/join_keys-extract.R" class="hidden">
               <table class="table-condensed">
                 <tbody>
                   <tr class="never">
                     <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Variable labels</pre>
+                      <pre class="language-r">#' @rdname join_keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @order 2</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Get or set variable labels in a `data.frame`.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @section Functions:</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">5</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @details Variable labels can be stored as a `label` attribute set on individual variables.</pre>
+                      <pre class="language-r">#' - `x[datanames]`: Returns a subset of the `join_keys` object for</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">6</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' These functions get or set this attribute, either on all (`col_labels`) or some variables (`col_relabel`).</pre>
+                      <pre class="language-r">#' given `datanames`, including parent `datanames` and symmetric mirror keys between</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">7</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' `datanames` in the result.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">8</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param x (`data.frame` or `DataFrame`) data object</pre>
+                      <pre class="language-r">#' - `x[i, j]`: Returns join keys between datasets `i` and `j`,</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">9</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param fill (`logical(1)`) specifying what to return if variable has no label</pre>
+                      <pre class="language-r">#'   including implicit keys inferred from their relationship with a parent.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">10</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param value (`character`) vector of variable labels of length equal to number of columns in `x`;</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">11</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  if named, names must match variable names in `x` and will be used as key to set labels;</pre>
+                      <pre class="language-r">#' @param i,j indices specifying elements to extract or replace. Index should be a</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">12</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  use `NA` to remove label from variable</pre>
+                      <pre class="language-r">#' a character vector, but it can also take numeric, logical, `NULL` or missing.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">13</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param ... name-value pairs, where name corresponds to a variable name in `x`</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">14</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  and value is the new variable label; use `NA` to remove label from variable</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -7239,28 +3994,28 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">16</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">17</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' For `col_labels`, named character vector of variable labels, the names being the corresponding variable names.</pre>
+                      <pre class="language-r">#' # Getter for join_keys ---</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' If the `label` attribute is missing, the vector elements will be</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">19</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' the variable names themselves if `fill = TRUE` and `NA` if `fill = FALSE`.</pre>
+                      <pre class="language-r">#' jk["ds1", "ds2"]</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -7274,7 +4029,7 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">21</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' For `col_labels&lt;-` and `col_relabel`, copy of `x` with variable labels modified.</pre>
+                      <pre class="language-r">#' # Subsetting join_keys ----</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -7288,245 +4043,245 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">23</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">#' jk["ds1"]</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">24</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' x &lt;- iris</pre>
+                      <pre class="language-r">#' jk[1:2]</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">25</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' col_labels(x)</pre>
+                      <pre class="language-r">#' jk[c("ds1", "ds2")]</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">26</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' col_labels(x) &lt;- paste("label for", names(iris))</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">27</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' col_labels(x)</pre>
+                      <pre class="language-r">`[.join_keys` &lt;- function(x, i, j) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">28</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">35<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' y &lt;- col_relabel(x, Sepal.Length = "Sepal Length of iris flower")</pre>
+                      <pre class="language-r">  if (missing(i) &amp;&amp; missing(j)) {</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">29</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' col_labels(y)</pre>
+                      <pre class="language-r">    # because:</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">30</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    # - list(a = 1)[] returns list(a = 1)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">31</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @source These functions were taken from</pre>
+                      <pre class="language-r">    # - data.frame(a = 1)[] returns data.frame(a = 1)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">32</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' [formatters](https://cran.r-project.org/package=formatters) package, to reduce the complexity of</pre>
+                      <pre class="language-r">    return(x)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">33</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">34<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' the dependency tree and rewritten.</pre>
+                      <pre class="language-r">  } else if (!missing(i) &amp;&amp; is.null(i) || !missing(j) &amp;&amp; is.null(j)) {</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">34</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    # because list(a = 1)[NULL] returns NULL</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">35</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname col_labels</pre>
+                      <pre class="language-r">    # data.frame(a = 1)[NULL, NULL] returns data.frame(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">36</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">    return(join_keys())</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">37</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">32<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  } else if (!missing(i) &amp;&amp; !missing(j)) {</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">38</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">col_labels &lt;- function(x, fill = FALSE) {</pre>
+                      <pre class="language-r">    if (</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">39</td>
-                    <td class="coverage">16<em>x</em></td>
+                    <td class="coverage">8<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::test_multi_class(x, c("data.frame", "DataFrame"))</pre>
+                      <pre class="language-r">      !any(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">40</td>
-                    <td class="coverage">16<em>x</em></td>
+                    <td class="coverage">8<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_flag(fill)</pre>
+                      <pre class="language-r">        checkmate::test_string(i),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">41</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">8<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">        checkmate::test_number(i),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">42</td>
-                    <td class="coverage">16<em>x</em></td>
+                    <td class="coverage">8<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (ncol(x) == 0L) {</pre>
+                      <pre class="language-r">        checkmate::test_logical(i, len = length(x)) &amp;&amp; sum(j) == 1</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">43</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    return(character(0L))</pre>
+                      <pre class="language-r">      ) ||</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">44</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">8<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">        !any(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">45</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">8<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">          checkmate::test_string(j),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">46</td>
-                    <td class="coverage">14<em>x</em></td>
+                    <td class="coverage">8<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  labels &lt;- sapply(x, function(i) as.vector(attr(i, "label", exact = TRUE)), simplify = FALSE, USE.NAMES = TRUE)</pre>
+                      <pre class="language-r">          checkmate::test_number(j),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">47</td>
-                    <td class="coverage">14<em>x</em></td>
+                    <td class="coverage">8<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  mapply(</pre>
+                      <pre class="language-r">          checkmate::test_logical(j, len = length(x)) &amp;&amp; sum(j) == 1</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">48</td>
-                    <td class="coverage">14<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    function(name, label) {</pre>
+                      <pre class="language-r">        )</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">49</td>
-                    <td class="coverage">62<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      checkmate::assert_string(</pre>
+                      <pre class="language-r">    ) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">50</td>
-                    <td class="coverage">62<em>x</em></td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        label,</pre>
+                      <pre class="language-r">      stop(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">51</td>
-                    <td class="coverage">62<em>x</em></td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        .var.name = sprintf("\"label\" attribute of column \"%s\"", name),</pre>
+                      <pre class="language-r">        "join_keys[i, j] - Can't extract keys for multiple pairs.",</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">52</td>
-                    <td class="coverage">62<em>x</em></td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        null.ok = TRUE</pre>
+                      <pre class="language-r">        "When specifying a pair [i, j], both indices must point to a single key pair.\n",</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">53</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      )</pre>
+                      <pre class="language-r">        call. = FALSE</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">54</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    },</pre>
+                      <pre class="language-r">      )</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">55</td>
-                    <td class="coverage">14<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    name = names(x),</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">56</td>
-                    <td class="coverage">14<em>x</em></td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    label = labels</pre>
+                      <pre class="language-r">    if (is.numeric(i)) i &lt;- names(x)[i]</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">57</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
+                      <pre class="language-r">    if (is.numeric(j)) j &lt;- names(x)[j]</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -7538,4589 +4293,4446 @@ <h2>teal.data coverage - 89.08%</h2>
                   </tr>
                   <tr class="covered">
                     <td class="num">59</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="coverage">7<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  nulls &lt;- vapply(labels, is.null, logical(1L))</pre>
+                      <pre class="language-r">    subset_x &lt;- update_keys_given_parents(x[union(i, j)])</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">60</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="coverage">7<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (any(nulls)) {</pre>
+                      <pre class="language-r">    return(subset_x[[i]][[j]])</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">61</td>
-                    <td class="coverage">7<em>x</em></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    labels[nulls] &lt;-</pre>
+                      <pre class="language-r">  } else if (!missing(j)) {</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">62</td>
-                    <td class="coverage">7<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      if (fill) {</pre>
+                      <pre class="language-r">    # ie. select all keys which have j as dataset_2</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">63</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        colnames(x)[nulls]</pre>
+                      <pre class="language-r">    # since list is symmetrical it is equivalent to selecting by i</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">64</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      } else {</pre>
+                      <pre class="language-r">    i &lt;- j</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">65</td>
-                    <td class="coverage">7<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        NA_character_</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">66</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">67</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">  checkmate::assert(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">68</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">    combine = "or",</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">69</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  unlist(labels)</pre>
+                      <pre class="language-r">    checkmate::check_character(i),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">70</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">    checkmate::check_numeric(i),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">71</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">    checkmate::check_logical(i)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">72</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname col_labels</pre>
+                      <pre class="language-r">  )</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">73</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">74</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">`col_labels&lt;-` &lt;- function(x, value) {</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">75</td>
-                    <td class="coverage">13<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::test_multi_class(x, c("data.frame", "DataFrame"))</pre>
+                      <pre class="language-r">  # Convert integer/logical index to named index</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">76</td>
-                    <td class="coverage">13<em>x</em></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_character(value)</pre>
+                      <pre class="language-r">  if (checkmate::test_numeric(i) || checkmate::test_logical(i)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">77</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_true(</pre>
+                      <pre class="language-r">    i &lt;- names(x)[i]</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">78</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    ncol(x) == length(value),</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">79</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    .var.name = "Length of value is equal to the number of columns"</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">80</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
+                      <pre class="language-r">  # When retrieving a relationship pair, it will also return the symmetric key</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">81</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">  new_jk &lt;- new_join_keys()</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">82</td>
-                    <td class="coverage">11<em>x</em></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  varnames &lt;-</pre>
+                      <pre class="language-r">  queue &lt;- unique(i)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">83</td>
-                    <td class="coverage">11<em>x</em></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (is.null(names(value))) {</pre>
+                      <pre class="language-r">  bin &lt;- character(0)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">84</td>
-                    <td class="coverage">4<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      names(x)</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">85</td>
-                    <td class="coverage">11<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    } else if (any(names(value) == "")) {</pre>
+                      <pre class="language-r">  # Need to iterate on a mutating queue if subset of a dataset will also</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">86</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      specified_cols &lt;- names(value)[names(value) != ""]</pre>
+                      <pre class="language-r">  #  select its parent as that parent might have relationships with others</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">87</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      checkmate::assert_subset(specified_cols, names(x), .var.name = "names of value")</pre>
+                      <pre class="language-r">  #  already selected.</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">88</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      res &lt;- names(value)</pre>
+                      <pre class="language-r">  while (length(queue) &gt; 0) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">89</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage">53<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      res[res == ""] &lt;- setdiff(names(x), specified_cols)</pre>
+                      <pre class="language-r">    ix &lt;- queue[1]</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">90</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage">53<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      res</pre>
+                      <pre class="language-r">    queue &lt;- queue[-1]</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">91</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">53<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    } else {</pre>
+                      <pre class="language-r">    bin &lt;- c(bin, ix)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">92</td>
-                    <td class="coverage">4<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      checkmate::assert_set_equal(names(value), names(x), .var.name = "names of value")</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">93</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage">53<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      names(value)</pre>
+                      <pre class="language-r">    ix_parent &lt;- parent(x, ix)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">94</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">95</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">53<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">    if (checkmate::test_string(ix_parent, min.chars = 1) &amp;&amp; !ix_parent %in% c(queue, bin)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">96</td>
                     <td class="coverage">10<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  for (i in seq_along(value)) {</pre>
+                      <pre class="language-r">      queue &lt;- c(queue, ix_parent)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">97</td>
-                    <td class="coverage">40<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (is.na(value[i])) {</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">98</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      attr(x[[varnames[i]]], "label") &lt;- NULL</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">99</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">53<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    } else {</pre>
+                      <pre class="language-r">    ix_valid_names &lt;- names(x[[ix]]) %in% c(queue, bin)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">100</td>
-                    <td class="coverage">38<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      attr(x[[varnames[i]]], "label") &lt;- value[[i]]</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">101</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">53<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">    new_jk[[ix]] &lt;- x[[ix]][ix_valid_names]</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">102</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">103</td>
-                    <td class="coverage">10<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x</pre>
+                      <pre class="language-r">    # Add primary key of parent</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">104</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">53<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">    if (length(ix_parent) &gt; 0) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">105</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">20<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">      new_jk[[ix_parent]][[ix_parent]] &lt;- x[[ix_parent]][[ix_parent]]</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">106</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname col_labels</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">107</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">108</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">col_relabel &lt;- function(x, ...) {</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">109</td>
-                    <td class="coverage">4<em>x</em></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::test_multi_class(x, c("data.frame", "DataFrame"))</pre>
+                      <pre class="language-r">  common_parents_ix &lt;- names(parents(x)) %in% names(new_jk) &amp;</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">110</td>
-                    <td class="coverage">4<em>x</em></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (missing(...)) {</pre>
+                      <pre class="language-r">    parents(x) %in% names(new_jk)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">111</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    return(x)</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">112</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">13<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">  if (any(common_parents_ix)) parents(new_jk) &lt;- parents(x)[common_parents_ix]</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">113</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  value &lt;- list(...)</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">114</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage">24<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  varnames &lt;- names(value)</pre>
+                      <pre class="language-r">  new_jk</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">115</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">116</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_subset(varnames, names(x), .var.name = "names of ...")</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">117</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  lapply(value, checkmate::assert_string, .var.name = "element of ...", na.ok = TRUE)</pre>
+                      <pre class="language-r">#' @rdname join_keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">118</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @order 2</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">119</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  for (i in seq_along(value)) {</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">120</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (is.na(value[i])) {</pre>
+                      <pre class="language-r">#' @param directed (`logical(1)`) Flag that indicates whether it should create</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">121</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      attr(x[[varnames[i]]], "label") &lt;- NULL</pre>
+                      <pre class="language-r">#' a parent-child relationship between the datasets.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">122</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    } else {</pre>
+                      <pre class="language-r">#'  - `TRUE` (default) `dataset_1` is the parent of `dataset_2`;</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">123</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      attr(x[[varnames[i]]], "label") &lt;- value[[i]]</pre>
+                      <pre class="language-r">#'  - `FALSE` when the relationship is undirected.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">124</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#' @section Functions:</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">125</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' - `x[i, j] &lt;- value`: Assignment of a key to pair `(i, j)`.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">126</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x</pre>
+                      <pre class="language-r">#' - `x[i] &lt;- value`: This (without `j` parameter) **is not** a supported</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">127</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#' operation for `join_keys`.</pre>
                     </td>
                   </tr>
-                </tbody>
-              </table>
-            </div>
-            <div id="R/teal_data-get_code.R" class="hidden">
-              <table class="table-condensed">
-                <tbody>
                   <tr class="never">
-                    <td class="num">1</td>
+                    <td class="num">128</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Get code from `teal_data` object</pre>
+                      <pre class="language-r">#' - `join_keys(x)[i, j] &lt;- value`: Assignment to `join_keys` object stored in `x`,</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">2</td>
+                    <td class="num">129</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' such as a `teal_data` object or `join_keys` object itself.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">3</td>
+                    <td class="num">130</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Retrieve code from `teal_data` object.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">4</td>
+                    <td class="num">131</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">5</td>
+                    <td class="num">132</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Retrieve code stored in `@code`, which (in principle) can be used to recreate all objects found in `@env`.</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">6</td>
+                    <td class="num">133</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Use `datanames` to limit the code to one or more of the datasets enumerated in `@datanames`.</pre>
+                      <pre class="language-r">#' # Setting a new primary key ---</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">7</td>
+                    <td class="num">134</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">8</td>
+                    <td class="num">135</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @section Extracting dataset-specific code:</pre>
+                      <pre class="language-r">#' jk["ds4", "ds4"] &lt;- "pk4"</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">9</td>
+                    <td class="num">136</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' When `datanames` is specified, the code returned will be limited  to the lines needed to _create_</pre>
+                      <pre class="language-r">#' jk["ds5", "ds5"] &lt;- "pk5"</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">10</td>
+                    <td class="num">137</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' the requested datasets. The code stored in the `@code` slot is analyzed statically to determine</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">11</td>
+                    <td class="num">138</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' which lines the datasets of interest depend upon. The analysis works well when objects are created</pre>
+                      <pre class="language-r">#' # Setting a single relationship pair ---</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">12</td>
+                    <td class="num">139</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' with standard infix assignment operators (see `?assignOps`) but it can fail in some situations.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">13</td>
+                    <td class="num">140</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' jk["ds1", "ds4"] &lt;- c("pk1" = "pk4")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">14</td>
+                    <td class="num">141</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Consider the following examples:</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">15</td>
+                    <td class="num">142</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' # Removing a key ---</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">16</td>
+                    <td class="num">143</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' _Case 1: Usual assignments._</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">17</td>
+                    <td class="num">144</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' ```r</pre>
+                      <pre class="language-r">#' jk["ds5", "ds5"] &lt;- NULL</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">18</td>
+                    <td class="num">145</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' data &lt;- teal_data() |&gt;</pre>
+                      <pre class="language-r">`[&lt;-.join_keys` &lt;- function(x, i, j, directed = TRUE, value) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">19</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">146</td>
+                    <td class="coverage">11<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   within({</pre>
+                      <pre class="language-r">  checkmate::assert_flag(directed)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">20</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">147</td>
+                    <td class="coverage">11<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     foo &lt;- function(x) {</pre>
+                      <pre class="language-r">  if (missing(i) || missing(j)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">21</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">148</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'       x + 1</pre>
+                      <pre class="language-r">    stop("join_keys[i, j] specify both indices to set a key pair.")</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">22</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">149</td>
+                    <td class="coverage">7<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     }</pre>
+                      <pre class="language-r">  } else if (!missing(i) &amp;&amp; is.null(i) || !missing(j) &amp;&amp; is.null(j)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">23</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">150</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     x &lt;- 0</pre>
+                      <pre class="language-r">    stop("join_keys[i, j] neither i nor j can be NULL.")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">24</td>
+                    <td class="num">151</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     y &lt;- foo(x)</pre>
+                      <pre class="language-r">  } else if (</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">25</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">152</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   })</pre>
+                      <pre class="language-r">    !any(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">26</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">153</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' get_code(data, datanames = "y")</pre>
+                      <pre class="language-r">      checkmate::test_string(i),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">27</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">154</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' ```</pre>
+                      <pre class="language-r">      checkmate::test_number(i),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">28</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">155</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' `x` has no dependencies, so `get_code(data, datanames = "x")` will return only the second call.\cr</pre>
+                      <pre class="language-r">      checkmate::test_logical(i, len = length(x)) &amp;&amp; sum(j) == 1</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">29</td>
+                    <td class="num">156</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' `y` depends on `x` and `foo`, so `get_code(data, datanames = "y")` will contain all three calls.</pre>
+                      <pre class="language-r">    ) ||</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">30</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">157</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      !any(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">31</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">158</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' _Case 2: Some objects are created by a function's side effects._</pre>
+                      <pre class="language-r">        checkmate::test_string(j),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">32</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">159</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' ```r</pre>
+                      <pre class="language-r">        checkmate::test_number(j),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">33</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">160</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' data &lt;- teal_data() |&gt;</pre>
+                      <pre class="language-r">        checkmate::test_logical(j, len = length(x)) &amp;&amp; sum(j) == 1</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">34</td>
+                    <td class="num">161</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   within({</pre>
+                      <pre class="language-r">      )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">35</td>
+                    <td class="num">162</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     foo &lt;- function() {</pre>
+                      <pre class="language-r">  ) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">36</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">163</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'       x &lt;&lt;- x + 1</pre>
+                      <pre class="language-r">    stop(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">37</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">164</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     }</pre>
+                      <pre class="language-r">      "join_keys[i, j] &lt;- Can't set keys to specified indices.\n",</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">38</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">165</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     x &lt;- 0</pre>
+                      <pre class="language-r">      "When setting pair [i, j], both indices must point to a single key pair.\n",</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">39</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">166</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     foo()</pre>
+                      <pre class="language-r">      call. = FALSE</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">40</td>
+                    <td class="num">167</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     y &lt;- x</pre>
+                      <pre class="language-r">    )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">41</td>
+                    <td class="num">168</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   })</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">42</td>
+                    <td class="num">169</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' get_code(data, datanames = "y")</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">43</td>
+                    <td class="num">170</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' ```</pre>
+                      <pre class="language-r">  # Handle join key removal separately</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">44</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">171</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Here, `y` depends on `x` but `x` is modified by `foo` as a side effect (not by reassignment)</pre>
+                      <pre class="language-r">  if (is.null(value)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">45</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">172</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' and so `get_code(data, datanames = "y")` will not return the `foo()` call.\cr</pre>
+                      <pre class="language-r">    x[[i]][[j]] &lt;- NULL</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">46</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">173</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' To overcome this limitation, code dependencies can be specified manually.</pre>
+                      <pre class="language-r">    return(x)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">47</td>
+                    <td class="num">174</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Lines where side effects occur can be flagged by adding "`# @linksto &lt;object name&gt;`" at the end.\cr</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">48</td>
+                    <td class="num">175</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Note that `within` evaluates code passed to `expr` as is and comments are ignored.</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">49</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">176</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' In order to include comments in code one must use the `eval_code` function instead.</pre>
+                      <pre class="language-r">  c(x, join_key(i, j, value, directed))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">50</td>
+                    <td class="num">177</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">51</td>
+                    <td class="num">178</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' ```r</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">52</td>
+                    <td class="num">179</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' data &lt;- teal_data() |&gt;</pre>
+                      <pre class="language-r">#' @rdname join_keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">53</td>
+                    <td class="num">180</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   eval_code("</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">54</td>
+                    <td class="num">181</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     foo &lt;- function() {</pre>
+                      <pre class="language-r">#' @order 1000</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">55</td>
+                    <td class="num">182</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'       x &lt;&lt;- x + 1</pre>
+                      <pre class="language-r">#' @usage ## Preferred method is x[i, j] &lt;- value</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">56</td>
+                    <td class="num">183</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     }</pre>
+                      <pre class="language-r">#' x[[i]][[j]] &lt;- value</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">57</td>
+                    <td class="num">184</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     x &lt;- 0</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">58</td>
+                    <td class="num">185</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     foo() # @linksto x</pre>
+                      <pre class="language-r">#' @section Functions:</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">59</td>
+                    <td class="num">186</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'     y &lt;- x</pre>
+                      <pre class="language-r">#' - `x[[i]][[j]] &lt;- value`: It is equivalent as  `x[i, j] &lt;- value`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">60</td>
+                    <td class="num">187</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   ")</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">61</td>
+                    <td class="num">188</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' get_code(data, datanames = "y")</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">62</td>
+                    <td class="num">189</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' ```</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">63</td>
+                    <td class="num">190</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Now the `foo()` call will be properly included in the code required to recreate `y`.</pre>
+                      <pre class="language-r">#' # Setting via x[[i]] &lt;- value ---</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">64</td>
+                    <td class="num">191</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">65</td>
+                    <td class="num">192</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Note that two functions that create objects as side effects, `assign` and `data`, are handled automatically.</pre>
+                      <pre class="language-r">#' jk &lt;- join_keys()</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">66</td>
+                    <td class="num">193</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' jk[["ds6"]][["ds6"]] &lt;- "pk6"</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">67</td>
+                    <td class="num">194</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Here are known cases where manual tagging is necessary:</pre>
+                      <pre class="language-r">#' jk[["ds7"]] &lt;- list(ds7 = "pk7", ds6 = c(pk7 = "pk6"))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">68</td>
+                    <td class="num">195</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - non-standard assignment operators, _e.g._ `%&lt;&gt;%`</pre>
+                      <pre class="language-r">#' jk[["ds7"]][["ds7"]] &lt;- NULL # removes key</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">69</td>
+                    <td class="num">196</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - objects used as conditions in `if` statements: `if (&lt;condition&gt;)`</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">70</td>
+                    <td class="num">197</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - objects used to iterate over in `for` loops: `for(i in &lt;sequence&gt;)`</pre>
+                      <pre class="language-r">#' jk</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">71</td>
+                    <td class="num">198</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - creating and evaluating language objects, _e.g._ `eval(&lt;call&gt;)`</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">72</td>
+                    <td class="num">199</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @noRd</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">73</td>
+                    <td class="num">200</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">`[[&lt;-.join_keys` &lt;- function(x, i, value) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">74</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">201</td>
+                    <td class="coverage">397<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param object (`teal_data`)</pre>
+                      <pre class="language-r">  checkmate::assert(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">75</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">202</td>
+                    <td class="coverage">397<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param datanames `r lifecycle::badge("experimental")` (`character`) vector of dataset names to return the code for.</pre>
+                      <pre class="language-r">    combine = "or",</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">76</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">203</td>
+                    <td class="coverage">397<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' For more details see the "Extracting dataset-specific code" section.</pre>
+                      <pre class="language-r">    checkmate::check_string(i),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">77</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">204</td>
+                    <td class="coverage">397<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param deparse (`logical`) flag specifying whether to return code as `character` (`deparse = TRUE`) or as</pre>
+                      <pre class="language-r">    checkmate::check_number(i),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">78</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">205</td>
+                    <td class="coverage">397<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' `expression` (`deparse = FALSE`).</pre>
+                      <pre class="language-r">    checkmate::check_logical(i, len = length(x))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">79</td>
+                    <td class="num">206</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param ... Parameters passed to internal methods. Currently, the only supported parameter is `check_names`</pre>
+                      <pre class="language-r">  )</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">80</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">207</td>
+                    <td class="coverage">397<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' (`logical(1)`) flag,  which is `TRUE` by default. Function warns about missing objects, if they do not exist in</pre>
+                      <pre class="language-r">  checkmate::assert_list(value, names = "named", types = "character", null.ok = TRUE)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">81</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">208</td>
+                    <td class="coverage">390<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' `code` but are passed in `datanames`. To remove the warning, set `check_names = FALSE`.</pre>
+                      <pre class="language-r">  if (checkmate::test_numeric(i) || checkmate::test_logical(i)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">82</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">209</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    i &lt;- names(x)[[i]]</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">83</td>
+                    <td class="num">210</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">84</td>
+                    <td class="num">211</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Either a character string or an expression. If `datanames` is used to request a specific dataset,</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">85</td>
+                    <td class="num">212</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' only code that _creates_ that dataset (not code that uses it) is returned. Otherwise, all contents of `@code`.</pre>
+                      <pre class="language-r">  # Normalize values</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">86</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">213</td>
+                    <td class="coverage">390<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  norm_value &lt;- lapply(seq_along(value), function(.x) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">87</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">214</td>
+                    <td class="coverage">551<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">    join_key(i, names(value)[.x], value[[.x]])</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">88</td>
+                    <td class="num">215</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' tdata1 &lt;- teal_data()</pre>
+                      <pre class="language-r">  })</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">89</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">216</td>
+                    <td class="coverage">390<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' tdata1 &lt;- within(tdata1, {</pre>
+                      <pre class="language-r">  names(norm_value) &lt;- names(value)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">90</td>
+                    <td class="num">217</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   a &lt;- 1</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">91</td>
+                    <td class="num">218</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   b &lt;- a^5</pre>
+                      <pre class="language-r">  # Check if multiple modifications don't have a conflict</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">92</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">219</td>
+                    <td class="coverage">390<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   c &lt;- list(x = 2)</pre>
+                      <pre class="language-r">  repeated_value_ix &lt;- names(value) %in% names(value)[duplicated(names(value))]</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">93</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">220</td>
+                    <td class="coverage">390<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' })</pre>
+                      <pre class="language-r">  repeated &lt;- norm_value[repeated_value_ix]</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">94</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">221</td>
+                    <td class="coverage">390<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' get_code(tdata1)</pre>
+                      <pre class="language-r">  vapply(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">95</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">222</td>
+                    <td class="coverage">390<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' get_code(tdata1, datanames = "a")</pre>
+                      <pre class="language-r">    seq_along(repeated),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">96</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">223</td>
+                    <td class="coverage">390<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' get_code(tdata1, datanames = "b")</pre>
+                      <pre class="language-r">    function(.ix, .x_value = repeated[[.ix]], .x_name = names(.x_value[[1]])) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">97</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">224</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      assert_compatible_keys2(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">98</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">225</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' tdata2 &lt;- teal_data(x1 = iris, code = "x1 &lt;- iris")</pre>
+                      <pre class="language-r">        .x_value,</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">99</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">226</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' get_code(tdata2)</pre>
+                      <pre class="language-r">        unlist(unname(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">100</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">227</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' get_code(verify(tdata2))</pre>
+                      <pre class="language-r">          repeated[-.ix][names(repeated[-.ix]) == .x_name]</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">101</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">228</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">        ), recursive = FALSE)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">102</td>
+                    <td class="num">229</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname get_code</pre>
+                      <pre class="language-r">      )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">103</td>
+                    <td class="num">230</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @aliases get_code,teal_data-method</pre>
+                      <pre class="language-r">    },</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">104</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">231</td>
+                    <td class="coverage">390<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    logical(1)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">105</td>
+                    <td class="num">232</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">  )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">106</td>
+                    <td class="num">233</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">setMethod("get_code", signature = "teal_data", definition = function(object, deparse = TRUE, datanames = NULL, ...) {</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">107</td>
-                    <td class="coverage">64<em>x</em></td>
+                    <td class="num">234</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_character(datanames, min.len = 1L, null.ok = TRUE)</pre>
+                      <pre class="language-r">  norm_value &lt;- lapply(norm_value, function(x) x[[1]][[1]])</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">108</td>
-                    <td class="coverage">64<em>x</em></td>
+                    <td class="num">235</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_flag(deparse)</pre>
+                      <pre class="language-r">  names(norm_value) &lt;- names(value)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">109</td>
+                    <td class="num">236</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">110</td>
+                    <td class="num">237</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # Normalize in case special it is backticked</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">111</td>
-                    <td class="coverage">64<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (!is.null(datanames)) {</pre>
+                      <pre class="language-r">  # Safe to do as duplicated are the same</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">112</td>
-                    <td class="coverage">60<em>x</em></td>
+                    <td class="num">238</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    datanames &lt;- gsub("^`(.*)`$", "\\1", datanames)</pre>
+                      <pre class="language-r">  norm_value[duplicated(names(norm_value))] &lt;- NULL</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">113</td>
+                    <td class="num">239</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">114</td>
+                    <td class="num">240</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">  # Keep only elements with length &gt; 0L</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">115</td>
-                    <td class="coverage">64<em>x</em></td>
+                    <td class="num">241</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  code &lt;- if (!is.null(datanames)) {</pre>
+                      <pre class="language-r">  norm_value &lt;- Filter(length, norm_value)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">116</td>
-                    <td class="coverage">60<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">242</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    get_code_dependency(object@code, datanames, ...)</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">117</td>
+                    <td class="num">243</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else {</pre>
+                      <pre class="language-r">  # Remove classes to use list-based get/assign operations</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">118</td>
-                    <td class="coverage">4<em>x</em></td>
+                    <td class="num">244</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    object@code</pre>
+                      <pre class="language-r">  new_x &lt;- unclass(x)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">119</td>
+                    <td class="num">245</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">120</td>
+                    <td class="num">246</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">  # In case a pair is removed, also remove the symmetric pair and update parents</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">121</td>
-                    <td class="coverage">64<em>x</em></td>
+                    <td class="num">247</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (deparse) {</pre>
+                      <pre class="language-r">  removed_names &lt;- setdiff(names(new_x[[i]]), names(norm_value))</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">122</td>
-                    <td class="coverage">63<em>x</em></td>
+                    <td class="num">248</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (length(code) == 0) {</pre>
+                      <pre class="language-r">  for (.x in removed_names) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">123</td>
+                    <td class="num">249</td>
                     <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      code</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">124</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    } else {</pre>
+                      <pre class="language-r">    if (identical(parent(x, .x), i)) attr(new_x, "parents")[[.x]] &lt;- NULL</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">125</td>
-                    <td class="coverage">61<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      paste(code, collapse = "\n")</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">126</td>
-                    <td class="coverage"></td>
+                    <td class="num">250</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">    if (identical(parent(x, i), .x)) attr(new_x, "parents")[[i]] &lt;- NULL</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">127</td>
+                    <td class="num">251</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else {</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">128</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="num">252</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    parse(text = paste(c("{", code, "}"), collapse = "\n"), keep.source = TRUE)</pre>
+                      <pre class="language-r">    new_x[[.x]][[i]] &lt;- NULL</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">129</td>
+                    <td class="num">253</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">130</td>
+                    <td class="num">254</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">})</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                </tbody>
-              </table>
-            </div>
-            <div id="R/utils-get_code_dependency.R" class="hidden">
-              <table class="table-condensed">
-                <tbody>
-                  <tr class="never">
-                    <td class="num">1</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">255</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"># get_code_dependency ----</pre>
+                      <pre class="language-r">  new_x[[i]] &lt;- norm_value</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">2</td>
+                    <td class="num">256</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">3</td>
+                    <td class="num">257</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Get code dependency of an object</pre>
+                      <pre class="language-r">  # Iterate on all new values to create symmetrical pair</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">4</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">258</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  for (ds2 in names(norm_value)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">5</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">259</td>
+                    <td class="coverage">310<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Extract subset of code required to reproduce specific object(s), including code producing side-effects.</pre>
+                      <pre class="language-r">    if (ds2 == i) next</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">6</td>
+                    <td class="num">260</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">7</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">261</td>
+                    <td class="coverage">237<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Given a character vector with code, this function will extract the part of the code responsible for creating</pre>
+                      <pre class="language-r">    keep_value &lt;- if (is.null(x)) list() else new_x[[ds2]]</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">8</td>
+                    <td class="num">262</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' the variables specified by `names`.</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">9</td>
+                    <td class="num">263</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' This includes the final call that creates the variable(s) in question as well as all _parent calls_,</pre>
+                      <pre class="language-r">    # Invert key</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">10</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">264</td>
+                    <td class="coverage">237<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' _i.e._ calls that create variables used in the final call and their parents, etc.</pre>
+                      <pre class="language-r">    new_value &lt;- stats::setNames(names(norm_value[[ds2]]), norm_value[[ds2]])</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">11</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">265</td>
+                    <td class="coverage">237<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Also included are calls that create side-effects like establishing connections.</pre>
+                      <pre class="language-r">    keep_value[[i]] &lt;- new_value</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">12</td>
+                    <td class="num">266</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">13</td>
+                    <td class="num">267</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' It is assumed that object dependency is established by using three assignment operators: `&lt;-`, `=`, and `-&gt;` .</pre>
+                      <pre class="language-r">    # Assign symmetrical</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">14</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">268</td>
+                    <td class="coverage">237<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Other assignment methods (`assign`, `&lt;&lt;-`) or non-standard-evaluation methods are not supported.</pre>
+                      <pre class="language-r">    new_x[[ds2]] &lt;- keep_value</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">15</td>
+                    <td class="num">269</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">16</td>
+                    <td class="num">270</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Side-effects are not detected automatically and must be marked in the code.</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">17</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">271</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Add `# @linksto object` at the end of a line where a side-effect occurs to specify that this line is required</pre>
+                      <pre class="language-r">  preserve_attr &lt;- attributes(new_x)[!names(attributes(new_x)) %in% "names"]</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">18</td>
+                    <td class="num">272</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' to reproduce a variable called `object`.</pre>
+                      <pre class="language-r">  # Remove NULL or empty keys</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">19</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">273</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  new_x &lt;- Filter(function(x) length(x) != 0L, new_x)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">20</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">274</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param code `character` with the code.</pre>
+                      <pre class="language-r">  attributes(new_x) &lt;- utils::modifyList(attributes(new_x), preserve_attr)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">21</td>
+                    <td class="num">275</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param names `character` vector of object names.</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">22</td>
+                    <td class="num">276</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param check_names `logical(1)` flag specifying if a warning for non-existing names should be displayed.</pre>
+                      <pre class="language-r">  #</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">23</td>
+                    <td class="num">277</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  # restore class</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">24</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">278</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return Character vector, a subset of `code`.</pre>
+                      <pre class="language-r">  class(new_x) &lt;- class(x)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">25</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">279</td>
+                    <td class="coverage">389<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Note that subsetting is actually done on the calls `code`, not necessarily on the elements of the vector.</pre>
+                      <pre class="language-r">  new_x</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">26</td>
+                    <td class="num">280</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
+                </tbody>
+              </table>
+            </div>
+            <div id="R/join_key.R" class="hidden">
+              <table class="table-condensed">
+                <tbody>
                   <tr class="never">
-                    <td class="num">27</td>
+                    <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">#' Create a relationship between a pair of datasets</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">28</td>
+                    <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">get_code_dependency &lt;- function(code, names, check_names = TRUE) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">29</td>
-                    <td class="coverage">60<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_character(code)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">30</td>
-                    <td class="coverage">60<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_character(names, any.missing = FALSE)</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">31</td>
+                    <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">32</td>
-                    <td class="coverage">60<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (identical(code, character(0)) || identical(trimws(code), "")) {</pre>
+                      <pre class="language-r">#' @description</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">33</td>
-                    <td class="coverage">2<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">4</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    return(code)</pre>
+                      <pre class="language-r">#' `r lifecycle::badge("stable")`</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">34</td>
+                    <td class="num">5</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">35</td>
+                    <td class="num">6</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' Create a relationship between two datasets, `dataset_1` and `dataset_2`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">36</td>
+                    <td class="num">7</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # If code is bound in curly brackets, remove them.</pre>
+                      <pre class="language-r">#' By default, this function establishes a directed relationship with `dataset_1` as the parent.</pre>
                     </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">37</td>
-                    <td class="coverage">58<em>x</em></td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">8</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  tcode &lt;- trimws(code)</pre>
+                      <pre class="language-r">#' If `dataset_2` is not specified, the function creates a primary key for `dataset_1`.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">38</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">9</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (any(grepl("^\\{.*\\}$", tcode))) {</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">39</td>
-                    <td class="coverage">2<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">10</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    code &lt;- sub("^\\{(.*)\\}$", "\\1", tcode)</pre>
+                      <pre class="language-r">#' @param dataset_1,dataset_2 (`character(1)`) Dataset names. When `dataset_2` is omitted,</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">40</td>
+                    <td class="num">11</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' a primary key for `dataset_1` is created.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">41</td>
+                    <td class="num">12</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @param keys (optionally named `character`) Column mapping between the datasets,</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">42</td>
+                    <td class="num">13</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' where `names(keys)` maps columns in `dataset_1` corresponding to columns of</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">43</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">14</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  code &lt;- parse(text = code, keep.source = TRUE)</pre>
+                      <pre class="language-r">#' `dataset_2` given by the elements of `keys`.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">44</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">15</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  pd &lt;- utils::getParseData(code)</pre>
+                      <pre class="language-r">#' - If unnamed, the same column names are used for both datasets.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">45</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">16</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  pd &lt;- normalize_pd(pd)</pre>
+                      <pre class="language-r">#' - If any element of the `keys` vector is empty with a non-empty name, then the name is</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">46</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">17</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  calls_pd &lt;- extract_calls(pd)</pre>
+                      <pre class="language-r">#' used for both datasets.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">47</td>
+                    <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @param directed (`logical(1)`) Flag that indicates whether it should create</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">48</td>
+                    <td class="num">19</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' a parent-child relationship between the datasets.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">49</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">20</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (check_names) {</pre>
+                      <pre class="language-r">#'  - `TRUE` (default) `dataset_1` is the parent of `dataset_2`;</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">50</td>
+                    <td class="num">21</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # Detect if names are actually in code.</pre>
+                      <pre class="language-r">#'  - `FALSE` when the relationship is undirected.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">51</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">22</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    symbols &lt;- unlist(lapply(calls_pd, function(call) call[call$token == "SYMBOL", "text"]))</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">52</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">23</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (any(pd$text == "assign")) {</pre>
+                      <pre class="language-r">#' @return object of class `join_key_set` to be passed into `join_keys` function.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">53</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">24</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      assign_calls &lt;- Filter(function(call) find_call(call, "assign"), calls_pd)</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">54</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">25</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      ass_str &lt;- unlist(lapply(assign_calls, function(call) call[call$token == "STR_CONST", "text"]))</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">55</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">26</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      ass_str &lt;- gsub("^['\"]|['\"]$", "", ass_str)</pre>
+                      <pre class="language-r">#' join_key("d1", "d2", c("A"))</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">56</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">27</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      symbols &lt;- c(ass_str, symbols)</pre>
+                      <pre class="language-r">#' join_key("d1", "d2", c("A" = "B"))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">57</td>
+                    <td class="num">28</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#' join_key("d1", "d2", c("A" = "B", "C"))</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">58</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">29</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (!all(names %in% unique(symbols))) {</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">59</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">30</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      warning("Object(s) not found in code: ", toString(setdiff(names, symbols)))</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">60</td>
+                    <td class="num">31</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#' @seealso [join_keys()], [parents()]</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">61</td>
+                    <td class="num">32</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">62</td>
+                    <td class="num">33</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">join_key &lt;- function(dataset_1, dataset_2 = dataset_1, keys, directed = TRUE) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">63</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">34</td>
+                    <td class="coverage">1103<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  graph &lt;- code_graph(calls_pd)</pre>
+                      <pre class="language-r">  checkmate::assert_string(dataset_1)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">64</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">35</td>
+                    <td class="coverage">1103<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  ind &lt;- unlist(lapply(names, function(x) graph_parser(x, graph)))</pre>
+                      <pre class="language-r">  checkmate::assert_string(dataset_2)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">65</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">36</td>
+                    <td class="coverage">1100<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">  checkmate::assert_character(keys, any.missing = FALSE)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">66</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">37</td>
+                    <td class="coverage">1095<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  lib_ind &lt;- detect_libraries(calls_pd)</pre>
+                      <pre class="language-r">  checkmate::assert_flag(directed)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">67</td>
+                    <td class="num">38</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">68</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">39</td>
+                    <td class="coverage">1095<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  as.character(code[sort(unique(c(lib_ind, ind)))])</pre>
+                      <pre class="language-r">  if (length(keys) &gt; 0) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">69</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">40</td>
+                    <td class="coverage">1093<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">    if (is.null(names(keys))) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">70</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">41</td>
+                    <td class="coverage">526<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">      names(keys) &lt;- keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">71</td>
+                    <td class="num">42</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Locate function call token</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">72</td>
+                    <td class="num">43</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">73</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">44</td>
+                    <td class="coverage">1093<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Determine which row of parsed data is specific `SYMBOL_FUNCTION_CALL` token.</pre>
+                      <pre class="language-r">    keys &lt;- trimws(keys)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">74</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">45</td>
+                    <td class="coverage">1093<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    names(keys) &lt;- trimws(names(keys))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">75</td>
+                    <td class="num">46</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Useful for determining occurrence of `assign` or `data` functions in an input call.</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">76</td>
+                    <td class="num">47</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    # Remove keys with empty value and without name</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">77</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">48</td>
+                    <td class="coverage">1093<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param call_pd `data.frame` as returned by `extract_calls()`</pre>
+                      <pre class="language-r">    if (any(keys == "" &amp; names(keys) == "")) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">78</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">49</td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param text `character(1)` to look for in `text` column of `call_pd`</pre>
+                      <pre class="language-r">      message("Key with an empty value and name are ignored.")</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">79</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">50</td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      keys &lt;- keys[keys != "" &amp; names(keys) != ""]</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">80</td>
+                    <td class="num">51</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">81</td>
+                    <td class="num">52</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Single integer specifying row in `call_pd` where `token` is `SYMBOL_FUNCTION_CALL` and `text` is `text`.</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">82</td>
+                    <td class="num">53</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' 0 if not found.</pre>
+                      <pre class="language-r">    # Set name of keys without one: c("A") -&gt; c("A" = "A")</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">83</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">54</td>
+                    <td class="coverage">1093<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">    if (any(names(keys) == "")) {</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">55</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      names(keys)[names(keys) == ""] &lt;- keys[names(keys) == ""]</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">84</td>
+                    <td class="num">56</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">85</td>
+                    <td class="num">57</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">86</td>
+                    <td class="num">58</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">find_call &lt;- function(call_pd, text) {</pre>
+                      <pre class="language-r">    # Set value of keys with empty string, but non-empty name: c("A" = "") -&gt; c("A" = "A")</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">87</td>
-                    <td class="coverage">405<em>x</em></td>
+                    <td class="num">59</td>
+                    <td class="coverage">1093<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::check_data_frame(call_pd)</pre>
+                      <pre class="language-r">    if (any(keys == "")) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">88</td>
-                    <td class="coverage">405<em>x</em></td>
+                    <td class="num">60</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::check_names(call_pd, must.include = c("token", "text"))</pre>
+                      <pre class="language-r">      keys[keys == ""] &lt;- names(keys[keys == ""])</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">89</td>
-                    <td class="coverage">405<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">61</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::check_string(text)</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">90</td>
+                    <td class="num">62</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">91</td>
-                    <td class="coverage">405<em>x</em></td>
+                    <td class="num">63</td>
+                    <td class="coverage">1093<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  ans &lt;- which(call_pd$token == "SYMBOL_FUNCTION_CALL" &amp; call_pd$text == text)</pre>
+                      <pre class="language-r">    stopifnot(!is.null(names(keys)))</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">92</td>
-                    <td class="coverage">405<em>x</em></td>
+                    <td class="num">64</td>
+                    <td class="coverage">1093<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (length(ans)) {</pre>
+                      <pre class="language-r">    stopifnot(!anyDuplicated(keys))</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">93</td>
-                    <td class="coverage">25<em>x</em></td>
+                    <td class="num">65</td>
+                    <td class="coverage">1092<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    ans</pre>
+                      <pre class="language-r">    stopifnot(!anyDuplicated(names(keys)))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">94</td>
+                    <td class="num">66</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else {</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">95</td>
-                    <td class="coverage">380<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    0L</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">96</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">97</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">98</td>
-                    <td class="coverage"></td>
+                    <td class="num">67</td>
+                    <td class="coverage">1091<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">    if (dataset_1 == dataset_2 &amp;&amp; any(names(keys) != keys)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">99</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">68</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Split the result of `utils::getParseData()` into separate calls</pre>
+                      <pre class="language-r">      stop("Keys within a dataset must match exactly: keys = c('A' = 'B') are not allowed")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">100</td>
+                    <td class="num">69</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">101</td>
+                    <td class="num">70</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param pd (`data.frame`) A result of `utils::getParseData()`.</pre>
+                      <pre class="language-r">  } else {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">102</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">71</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    keys &lt;- NULL</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">103</td>
+                    <td class="num">72</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">104</td>
+                    <td class="num">73</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' A `list` of `data.frame`s.</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">105</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">74</td>
+                    <td class="coverage">1091<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Each element is a subset of `pd` corresponding to one call in the original code from which `pd` was obtained.</pre>
+                      <pre class="language-r">  parents &lt;- if (directed &amp;&amp; dataset_1 != dataset_2) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">106</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">75</td>
+                    <td class="coverage">413<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Only four columns (`"token"`, `"text"`, `"id"`, `"parent"`) are kept, the rest is discarded.</pre>
+                      <pre class="language-r">    stats::setNames(list(dataset_1), dataset_2)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">107</td>
+                    <td class="num">76</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  } else {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">108</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">77</td>
+                    <td class="coverage">678<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">    list()</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">109</td>
+                    <td class="num">78</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">110</td>
+                    <td class="num">79</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">extract_calls &lt;- function(pd) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">111</td>
-                    <td class="coverage">58<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  calls &lt;- lapply(</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">112</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">80</td>
+                    <td class="coverage">1091<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    pd[pd$parent == 0, "id"],</pre>
+                      <pre class="language-r">  structure(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">113</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">81</td>
+                    <td class="coverage">1091<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    function(parent) {</pre>
+                      <pre class="language-r">    list(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">114</td>
-                    <td class="coverage">194<em>x</em></td>
+                    <td class="num">82</td>
+                    <td class="coverage">1091<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      rbind(</pre>
+                      <pre class="language-r">      structure(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">115</td>
-                    <td class="coverage">194<em>x</em></td>
+                    <td class="num">83</td>
+                    <td class="coverage">1091<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        pd[pd$id == parent, c("token", "text", "id", "parent")],</pre>
+                      <pre class="language-r">        list(keys),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">116</td>
-                    <td class="coverage">194<em>x</em></td>
+                    <td class="num">84</td>
+                    <td class="coverage">1091<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        get_children(pd = pd, parent = parent)</pre>
+                      <pre class="language-r">        names = dataset_2</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">117</td>
+                    <td class="num">85</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">      )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">118</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">119</td>
+                    <td class="num">86</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
+                      <pre class="language-r">    ),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">120</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">87</td>
+                    <td class="coverage">1091<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  calls &lt;- Filter(function(call) !(nrow(call) == 1 &amp;&amp; call$token == "';'"), calls)</pre>
+                      <pre class="language-r">    names = dataset_1,</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">121</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">88</td>
+                    <td class="coverage">1091<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  calls &lt;- Filter(Negate(is.null), calls)</pre>
+                      <pre class="language-r">    class = "join_key_set",</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">122</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">89</td>
+                    <td class="coverage">1091<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  calls &lt;- fix_shifted_comments(calls)</pre>
+                      <pre class="language-r">    parents = parents</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">123</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">90</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  fix_arrows(calls)</pre>
+                      <pre class="language-r">  )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">124</td>
+                    <td class="num">91</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">}</pre>
                     </td>
                   </tr>
+                </tbody>
+              </table>
+            </div>
+            <div id="R/teal_data-class.R" class="hidden">
+              <table class="table-condensed">
+                <tbody>
                   <tr class="never">
-                    <td class="num">125</td>
+                    <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">setOldClass("join_keys")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">126</td>
+                    <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">127</td>
+                    <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r">#' Reproducible data</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">128</td>
+                    <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">get_children &lt;- function(pd, parent) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">129</td>
-                    <td class="coverage">2657<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  idx_children &lt;- abs(pd$parent) == parent</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">130</td>
-                    <td class="coverage">2657<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  children &lt;- pd[idx_children, c("token", "text", "id", "parent")]</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">131</td>
-                    <td class="coverage">2657<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (nrow(children) == 0) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">132</td>
-                    <td class="coverage">1588<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    return(NULL)</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">133</td>
+                    <td class="num">5</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' Reproducible data container class. Inherits code tracking behavior from [`teal.code::qenv-class`].</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">134</td>
+                    <td class="num">6</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">135</td>
-                    <td class="coverage">1069<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  if (parent &gt; 0) {</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">136</td>
-                    <td class="coverage">1069<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">7</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    do.call(rbind, c(list(children), lapply(children$id, get_children, pd = pd)))</pre>
+                      <pre class="language-r">#' This class provides an isolated environment in which to store and process data with all code being recorded.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">137</td>
+                    <td class="num">8</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' The environment, code, data set names, and data joining keys are stored in their respective slots.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">138</td>
+                    <td class="num">9</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#' These slots should never be accessed directly, use the provided get/set functions.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">139</td>
+                    <td class="num">10</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">140</td>
+                    <td class="num">11</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Fixes edge case of comments being shifted to the next call.</pre>
+                      <pre class="language-r">#' As code is evaluated in `teal_data`, messages and warnings are stored in their respective slots.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">141</td>
+                    <td class="num">12</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">#' If errors are raised, a `qenv.error` object is returned.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">142</td>
+                    <td class="num">13</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">143</td>
+                    <td class="num">14</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">fix_shifted_comments &lt;- function(calls) {</pre>
+                      <pre class="language-r">#' @name teal_data-class</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">144</td>
+                    <td class="num">15</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # If the first or the second token is a @linksto COMMENT,</pre>
+                      <pre class="language-r">#' @rdname teal_data-class</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">145</td>
+                    <td class="num">16</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  #  then it belongs to the previous call.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">146</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">17</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (length(calls) &gt;= 2) {</pre>
+                      <pre class="language-r">#' @slot env (`environment`) environment containing data sets and possibly auxiliary variables.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">147</td>
-                    <td class="coverage">56<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">18</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    for (i in 2:length(calls)) {</pre>
+                      <pre class="language-r">#'  Access variables with [get_var()] or [`[[`].</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">148</td>
-                    <td class="coverage">134<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">19</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      comment_idx &lt;- grep("@linksto", calls[[i]][, "text"])</pre>
+                      <pre class="language-r">#'  No setter provided. Evaluate code to add variables into `@env`.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">149</td>
-                    <td class="coverage">134<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">20</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      if (isTRUE(comment_idx[1] &lt;= 2)) {</pre>
+                      <pre class="language-r">#' @slot code (`character`) vector representing code necessary to reproduce the contents of `@env`.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">150</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">21</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        calls[[i - 1]] &lt;- rbind(</pre>
+                      <pre class="language-r">#'  Access with [get_code()].</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">151</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">22</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          calls[[i - 1]],</pre>
+                      <pre class="language-r">#'  No setter provided. Evaluate code to append code to the slot.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">152</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">23</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          calls[[i]][seq_len(comment_idx[1]), ]</pre>
+                      <pre class="language-r">#' @slot id (`integer`) random identifier assigned to each element of `@code`. Used internally.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">153</td>
+                    <td class="num">24</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        )</pre>
+                      <pre class="language-r">#' @slot warnings (`character`) vector of warnings raised when evaluating code.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">154</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">25</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        calls[[i]] &lt;- calls[[i]][-seq_len(comment_idx[1]), ]</pre>
+                      <pre class="language-r">#'  Access with [get_warnings()].</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">155</td>
+                    <td class="num">26</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r">#' @slot messages (`character`) vector of messages raised when evaluating code.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">156</td>
+                    <td class="num">27</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#' @slot join_keys (`join_keys`) object specifying joining keys for data sets in `@env`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">157</td>
+                    <td class="num">28</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#'  Access or modify with [join_keys()].</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">158</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">29</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  Filter(nrow, calls)</pre>
+                      <pre class="language-r">#' @slot datanames (`character`) vector of names of data sets in `@env`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">159</td>
+                    <td class="num">30</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#'  Used internally to distinguish them from auxiliary variables.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">160</td>
+                    <td class="num">31</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#'  Access or modify with [datanames()].</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">161</td>
+                    <td class="num">32</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Fixes edge case of `&lt;-` assignment operator being called as function,</pre>
+                      <pre class="language-r">#' @slot verified (`logical(1)`) flag signifying that code in `@code` has been proven to yield contents of `@env`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">162</td>
+                    <td class="num">33</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' which is \code{`&lt;-`(y,x)} instead of traditional `y &lt;- x`.</pre>
+                      <pre class="language-r">#'  Used internally. See [`verify()`] for more details.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">163</td>
+                    <td class="num">34</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">164</td>
+                    <td class="num">35</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r">#' @import teal.code</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">165</td>
+                    <td class="num">36</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">fix_arrows &lt;- function(calls) {</pre>
+                      <pre class="language-r">#' @keywords internal</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">166</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">37</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_list(calls)</pre>
+                      <pre class="language-r">setClass(</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">167</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">38</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  lapply(calls, function(call) {</pre>
+                      <pre class="language-r">  Class = "teal_data",</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">168</td>
-                    <td class="coverage">191<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">39</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    sym_fun &lt;- call$token == "SYMBOL_FUNCTION_CALL"</pre>
+                      <pre class="language-r">  contains = "qenv",</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">169</td>
-                    <td class="coverage">191<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">40</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    call[sym_fun, ] &lt;- sub_arrows(call[sym_fun, ])</pre>
+                      <pre class="language-r">  slots = c(join_keys = "join_keys", datanames = "character", verified = "logical"),</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">170</td>
-                    <td class="coverage">191<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">41</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    call</pre>
+                      <pre class="language-r">  prototype = list(</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">171</td>
+                    <td class="num">42</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  })</pre>
+                      <pre class="language-r">    join_keys = join_keys(),</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">172</td>
+                    <td class="num">43</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">    datanames = character(0),</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">173</td>
+                    <td class="num">44</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">    verified = logical(0)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">174</td>
+                    <td class="num">45</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Execution of assignment operator substitutions for a call.</pre>
+                      <pre class="language-r">  )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">175</td>
+                    <td class="num">46</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">176</td>
+                    <td class="num">47</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">177</td>
+                    <td class="num">48</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">sub_arrows &lt;- function(call) {</pre>
+                      <pre class="language-r">#' Initialize `teal_data` object</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">178</td>
-                    <td class="coverage">191<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">49</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_data_frame(call)</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">179</td>
-                    <td class="coverage">191<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">50</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  map &lt;- data.frame(</pre>
+                      <pre class="language-r">#' @name new_teal_data</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">180</td>
-                    <td class="coverage">191<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">51</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    row.names = c("&lt;-", "&lt;&lt;-", "="),</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">181</td>
-                    <td class="coverage">191<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">52</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    token = rep("LEFT_ASSIGN", 3),</pre>
+                      <pre class="language-r">#' @param data (`named list`) of data objects.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">182</td>
-                    <td class="coverage">191<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">53</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    text = rep("&lt;-", 3)</pre>
+                      <pre class="language-r">#' @param code (`character` or `language`) code to reproduce the `data`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">183</td>
+                    <td class="num">54</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
+                      <pre class="language-r">#'   Accepts and stores comments also.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">184</td>
-                    <td class="coverage">191<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">55</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  sub_ids &lt;- call$text %in% rownames(map)</pre>
+                      <pre class="language-r">#' @param join_keys (`join_keys`) object</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">185</td>
-                    <td class="coverage">191<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">56</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  call[sub_ids, c("token", "text")] &lt;- map[call$text[sub_ids], ]</pre>
+                      <pre class="language-r">#' @param datanames (`character`) names of datasets passed to `data`.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">186</td>
-                    <td class="coverage">191<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">57</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  call</pre>
+                      <pre class="language-r">#'   Needed when non-dataset objects are needed in the `env` slot.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">187</td>
+                    <td class="num">58</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#' @rdname new_teal_data</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">188</td>
+                    <td class="num">59</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @keywords internal</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">189</td>
+                    <td class="num">60</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"># code_graph ----</pre>
+                      <pre class="language-r">new_teal_data &lt;- function(data,</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">190</td>
+                    <td class="num">61</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">                          code = character(0),</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">191</td>
+                    <td class="num">62</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Create object dependencies graph within parsed code</pre>
+                      <pre class="language-r">                          join_keys = join_keys(),</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">192</td>
+                    <td class="num">63</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">                          datanames = names(data)) {</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">64</td>
+                    <td class="coverage">48<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  checkmate::assert_list(data)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">193</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">65</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Builds dependency graph that identifies dependencies between objects in parsed code.</pre>
+                      <pre class="language-r">  checkmate::assert_class(join_keys, "join_keys")</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">194</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">66</td>
+                    <td class="coverage">23<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Helps understand which objects depend on which.</pre>
+                      <pre class="language-r">  if (is.null(datanames)) datanames &lt;- character(0) # todo: allow to specify</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">195</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">67</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  checkmate::assert_character(datanames)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">196</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">68</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param calls_pd `list` of `data.frame`s;</pre>
+                      <pre class="language-r">  if (!any(is.language(code), is.character(code))) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">197</td>
-                    <td class="coverage"></td>
+                  <tr class="missed">
+                    <td class="num">69</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  result of `utils::getParseData()` split into subsets representing individual calls;</pre>
+                      <pre class="language-r">    stop("`code` must be a character or language object.")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">198</td>
+                    <td class="num">70</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  created by `extract_calls()` function</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">199</td>
+                    <td class="num">71</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">200</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">72</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return</pre>
+                      <pre class="language-r">  if (is.language(code)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">201</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">73</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' A list (of length of input `calls_pd`) where each element represents one call.</pre>
+                      <pre class="language-r">    code &lt;- paste(lang2calls(code), collapse = "\n")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">202</td>
+                    <td class="num">74</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Each element is a character vector listing names of objects that depend on this call</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">203</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">75</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' and names of objects that this call depends on.</pre>
+                      <pre class="language-r">  if (length(code)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">204</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">76</td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Dependencies are listed after the `"&lt;-"` string, e.g. `c("a", "&lt;-", "b", "c")` means that in this call object `a`</pre>
+                      <pre class="language-r">    code &lt;- paste(code, collapse = "\n")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">205</td>
+                    <td class="num">77</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' depends on objects `b` and `c`.</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">206</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">78</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' If a call is tagged with `@linksto a`, then object `a` is understood to depend on that call.</pre>
+                      <pre class="language-r">  verified &lt;- (length(code) == 0L &amp;&amp; length(data) == 0L)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">207</td>
+                    <td class="num">79</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">208</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">80</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">  id &lt;- sample.int(.Machine$integer.max, size = length(code))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">209</td>
+                    <td class="num">81</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">210</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">82</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">code_graph &lt;- function(calls_pd) {</pre>
+                      <pre class="language-r">  new_env &lt;- rlang::env_clone(list2env(data), parent = parent.env(.GlobalEnv))</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">211</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">83</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  cooccurrence &lt;- extract_occurrence(calls_pd)</pre>
+                      <pre class="language-r">  lockEnvironment(new_env, bindings = TRUE)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">212</td>
+                    <td class="num">84</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">213</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">85</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  side_effects &lt;- extract_side_effects(calls_pd)</pre>
+                      <pre class="language-r">  datanames &lt;- .get_sorted_datanames(datanames = datanames, join_keys = join_keys, env = new_env)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">214</td>
+                    <td class="num">86</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">215</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">87</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  mapply(c, side_effects, cooccurrence, SIMPLIFY = FALSE)</pre>
+                      <pre class="language-r">  methods::new(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">216</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">88</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">    "teal_data",</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">217</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">89</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">    env = new_env,</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">218</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">90</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Extract object occurrence</pre>
+                      <pre class="language-r">    code = code,</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">219</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">91</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    warnings = rep("", length(code)),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">220</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">92</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Extracts objects occurrence within calls passed by `calls_pd`.</pre>
+                      <pre class="language-r">    messages = rep("", length(code)),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">221</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">93</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Also detects which objects depend on which within a call.</pre>
+                      <pre class="language-r">    id = id,</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">222</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">94</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    join_keys = join_keys,</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">223</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">95</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param calls_pd `list` of `data.frame`s;</pre>
+                      <pre class="language-r">    datanames = datanames,</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">224</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">96</td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  result of `utils::getParseData()` split into subsets representing individual calls;</pre>
+                      <pre class="language-r">    verified = verified</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">225</td>
+                    <td class="num">97</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  created by `extract_calls()` function</pre>
+                      <pre class="language-r">  )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">226</td>
+                    <td class="num">98</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
+                </tbody>
+              </table>
+            </div>
+            <div id="R/join_keys-print.R" class="hidden">
+              <table class="table-condensed">
+                <tbody>
                   <tr class="never">
-                    <td class="num">227</td>
+                    <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return</pre>
+                      <pre class="language-r">#' @rdname join_keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">228</td>
+                    <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' A list (of length of input `calls_pd`) where each element represents one call.</pre>
+                      <pre class="language-r">#' @order 7</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">229</td>
+                    <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Each element is a character vector listing names of objects that depend on this call</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">230</td>
+                    <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' and names of objects that this call depends on.</pre>
+                      <pre class="language-r">format.join_keys &lt;- function(x, ...) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">231</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">5</td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Dependencies are listed after the `"&lt;-"` string, e.g. `c("a", "&lt;-", "b", "c")` means that in this call object `a`</pre>
+                      <pre class="language-r">  if (length(x) &gt; 0) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">232</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">6</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' depends on objects `b` and `c`.</pre>
+                      <pre class="language-r">    my_parents &lt;- parents(x)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">233</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">7</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' If a call is tagged with `@linksto a`, then object `a` is understood to depend on that call.</pre>
+                      <pre class="language-r">    names_sorted &lt;- topological_sort(my_parents)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">234</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">8</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    names &lt;- union(names_sorted, names(x))</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">235</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">9</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">    x_implicit &lt;- update_keys_given_parents(x)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">236</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">10</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r">    out &lt;- lapply(names, function(i) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">237</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">11</td>
+                    <td class="coverage">15<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">extract_occurrence &lt;- function(calls_pd) {</pre>
+                      <pre class="language-r">      out_i &lt;- lapply(union(i, names(x[[i]])), function(j) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">238</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">12</td>
+                    <td class="coverage">35<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  is_in_function &lt;- function(x) {</pre>
+                      <pre class="language-r">        direction &lt;- if (identical(my_parents[[j]], i)) {</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">239</td>
+                    <td class="num">13</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # If an object is a function parameter,</pre>
+                      <pre class="language-r">          "  &lt;-- "</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">240</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">14</td>
+                    <td class="coverage">35<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # then in calls_pd there is a `SYMBOL_FORMALS` entry for that object.</pre>
+                      <pre class="language-r">        } else if (identical(my_parents[[i]], j)) {</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">241</td>
-                    <td class="coverage">177<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">15</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    function_id &lt;- x[x$token == "FUNCTION", "parent"]</pre>
+                      <pre class="language-r">          "  --&gt; "</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">242</td>
-                    <td class="coverage">177<em>x</em></td>
+                    <td class="num">16</td>
+                    <td class="coverage">35<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (length(function_id)) {</pre>
+                      <pre class="language-r">        } else if (!identical(i, j)) {</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">243</td>
-                    <td class="coverage">22<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">17</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      x$id %in% get_children(x, function_id[1])$id</pre>
+                      <pre class="language-r">          "  &lt;-&gt; "</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">244</td>
+                    <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    } else {</pre>
+                      <pre class="language-r">        } else {</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">245</td>
-                    <td class="coverage">155<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">19</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      rep(FALSE, nrow(x))</pre>
+                      <pre class="language-r">          ""</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">246</td>
+                    <td class="num">20</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">        }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">247</td>
+                    <td class="num">21</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">248</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">22</td>
+                    <td class="coverage">35<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  in_parenthesis &lt;- function(x) {</pre>
+                      <pre class="language-r">        keys &lt;- x[[i]][[j]]</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">249</td>
-                    <td class="coverage">154<em>x</em></td>
+                    <td class="num">23</td>
+                    <td class="coverage">35<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (any(x$token %in% c("LBB", "'['"))) {</pre>
+                      <pre class="language-r">        sprintf(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">250</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="num">24</td>
+                    <td class="coverage">35<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      id_start &lt;- min(x$id[x$token %in% c("LBB", "'['")])</pre>
+                      <pre class="language-r">          "%s%s: [%s]",</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">251</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="num">25</td>
+                    <td class="coverage">35<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      id_end &lt;- min(x$id[x$token == "']'"])</pre>
+                      <pre class="language-r">          direction, j,</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">252</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="num">26</td>
+                    <td class="coverage">35<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      x$text[x$token == "SYMBOL" &amp; x$id &gt; id_start &amp; x$id &lt; id_end]</pre>
+                      <pre class="language-r">          if (length(keys) == 0) "no primary keys" else toString(keys)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">253</td>
+                    <td class="num">27</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">        )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">254</td>
+                    <td class="num">28</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">      })</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">255</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">29</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  lapply(</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">256</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">30</td>
+                    <td class="coverage">15<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    calls_pd,</pre>
+                      <pre class="language-r">      implicit_datasets &lt;- setdiff(names(x_implicit[[i]]), names(x[[i]]))</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">257</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">31</td>
+                    <td class="coverage">15<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    function(call_pd) {</pre>
+                      <pre class="language-r">      if (length(implicit_datasets) &gt; 0) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">258</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">32</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      # Handle data(object)/data("object")/data(object, envir = ) independently.</pre>
+                      <pre class="language-r">        out_i &lt;- c(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">259</td>
-                    <td class="coverage">191<em>x</em></td>
+                    <td class="num">33</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      data_call &lt;- find_call(call_pd, "data")</pre>
+                      <pre class="language-r">          out_i,</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">260</td>
-                    <td class="coverage">191<em>x</em></td>
+                    <td class="num">34</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      if (data_call) {</pre>
+                      <pre class="language-r">          paste0(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">261</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="num">35</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        sym &lt;- call_pd[data_call + 1, "text"]</pre>
+                      <pre class="language-r">            "  --* (implicit via parent with): ",</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">262</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="num">36</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        return(c(gsub("^['\"]|['\"]$", "", sym), "&lt;-"))</pre>
+                      <pre class="language-r">            paste(implicit_datasets, collapse = ", ")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">263</td>
+                    <td class="num">37</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r">          )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">264</td>
+                    <td class="num">38</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      # Handle assign(x = ).</pre>
+                      <pre class="language-r">        )</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">265</td>
-                    <td class="coverage">188<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">39</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">      }</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">40</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      assign_call &lt;- find_call(call_pd, "assign")</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">266</td>
-                    <td class="coverage">188<em>x</em></td>
+                    <td class="num">41</td>
+                    <td class="coverage">15<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      if (assign_call) {</pre>
+                      <pre class="language-r">      paste(out_i, collapse = "\n")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">267</td>
+                    <td class="num">42</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        # Check if parameters were named.</pre>
+                      <pre class="language-r">    })</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">268</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">43</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        # "','" is for unnamed parameters, where "SYMBOL_SUB" is for named.</pre>
+                      <pre class="language-r">    paste(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">269</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">44</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        # "EQ_SUB" is for `=` appearing after the name of the named parameter.</pre>
+                      <pre class="language-r">      c(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">270</td>
-                    <td class="coverage">11<em>x</em></td>
+                    <td class="num">45</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        if (any(call_pd$token == "SYMBOL_SUB")) {</pre>
+                      <pre class="language-r">        sprintf("A join_keys object containing foreign keys between %s datasets:", length(x)),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">271</td>
-                    <td class="coverage">8<em>x</em></td>
+                    <td class="num">46</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          params &lt;- call_pd[call_pd$token %in% c("SYMBOL_SUB", "','", "EQ_SUB"), "text"]</pre>
+                      <pre class="language-r">        out</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">272</td>
+                    <td class="num">47</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          # Remove sequence of "=", ",".</pre>
+                      <pre class="language-r">      ),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">273</td>
-                    <td class="coverage">8<em>x</em></td>
+                    <td class="num">48</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          if (length(params &gt; 1)) {</pre>
+                      <pre class="language-r">      collapse = "\n"</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">274</td>
-                    <td class="coverage">8<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">49</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">            remove &lt;- integer(0)</pre>
+                      <pre class="language-r">    )</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">275</td>
-                    <td class="coverage">8<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">50</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">            for (i in 2:length(params)) {</pre>
+                      <pre class="language-r">  } else {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">276</td>
-                    <td class="coverage">36<em>x</em></td>
+                    <td class="num">51</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">              if (params[i - 1] == "=" &amp; params[i] == ",") {</pre>
+                      <pre class="language-r">    "An empty join_keys object."</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">277</td>
-                    <td class="coverage">8<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">52</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">                remove &lt;- c(remove, i - 1, i)</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">278</td>
+                    <td class="num">53</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">              }</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">279</td>
+                    <td class="num">54</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">            }</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">280</td>
-                    <td class="coverage">7<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">55</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">            if (length(remove)) params &lt;- params[-remove]</pre>
+                      <pre class="language-r">#' @rdname join_keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">281</td>
+                    <td class="num">56</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#' @order 7</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">57</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#' @export</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">58</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          }</pre>
+                      <pre class="language-r">print.join_keys &lt;- function(x, ...) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">282</td>
-                    <td class="coverage">8<em>x</em></td>
+                    <td class="num">59</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          pos &lt;- match("x", setdiff(params, ","), nomatch = match(",", params, nomatch = 0))</pre>
+                      <pre class="language-r">  cat(format(x, ...), "\n")</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">283</td>
-                    <td class="coverage">8<em>x</em></td>
+                    <td class="num">60</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          if (!pos) {</pre>
+                      <pre class="language-r">  invisible(x)</pre>
                     </td>
                   </tr>
-                  <tr class="missed">
-                    <td class="num">284</td>
-                    <td class="coverage">!</td>
+                  <tr class="never">
+                    <td class="num">61</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">            return(character(0L))</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
+                </tbody>
+              </table>
+            </div>
+            <div id="R/formatters_var_labels.R" class="hidden">
+              <table class="table-condensed">
+                <tbody>
                   <tr class="never">
-                    <td class="num">285</td>
+                    <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          }</pre>
+                      <pre class="language-r">#' Variable labels</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">286</td>
+                    <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          # pos is indicator of the place of 'x'</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">287</td>
+                    <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          # 1. All parameters are named, but none is 'x' - return(character(0L))</pre>
+                      <pre class="language-r">#' Get or set variable labels in a `data.frame`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">288</td>
+                    <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          # 2. Some parameters are named, 'x' is in named parameters: match("x", setdiff(params, ","))</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">289</td>
+                    <td class="num">5</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          # - check "x" in params being just a vector of named parameters.</pre>
+                      <pre class="language-r">#' @details Variable labels can be stored as a `label` attribute set on individual variables.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">290</td>
+                    <td class="num">6</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          # 3. Some parameters are named, 'x' is not in named parameters</pre>
+                      <pre class="language-r">#' These functions get or set this attribute, either on all (`col_labels`) or some variables (`col_relabel`).</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">291</td>
+                    <td class="num">7</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          # - check first appearance of "," (unnamed parameter) in vector parameters.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">292</td>
+                    <td class="num">8</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        } else {</pre>
+                      <pre class="language-r">#' @param x (`data.frame` or `DataFrame`) data object</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">293</td>
+                    <td class="num">9</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          # Object is the first entry after 'assign'.</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">294</td>
-                    <td class="coverage">3<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">          pos &lt;- 1</pre>
+                      <pre class="language-r">#' @param fill (`logical(1)`) specifying what to return if variable has no label</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">295</td>
+                    <td class="num">10</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        }</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">296</td>
-                    <td class="coverage">11<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        sym &lt;- call_pd[assign_call + pos, "text"]</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">297</td>
-                    <td class="coverage">11<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        return(c(gsub("^['\"]|['\"]$", "", sym), "&lt;-"))</pre>
+                      <pre class="language-r">#' @param value (`character`) vector of variable labels of length equal to number of columns in `x`;</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">298</td>
+                    <td class="num">11</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r">#'  if named, names must match variable names in `x` and will be used as key to set labels;</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">299</td>
+                    <td class="num">12</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#'  use `NA` to remove label from variable</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">300</td>
+                    <td class="num">13</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      # What occurs in a function body is not tracked.</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">301</td>
-                    <td class="coverage">177<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      x &lt;- call_pd[!is_in_function(call_pd), ]</pre>
+                      <pre class="language-r">#' @param ... name-value pairs, where name corresponds to a variable name in `x`</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">302</td>
-                    <td class="coverage">177<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">14</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      sym_cond &lt;- which(x$token %in% c("SPECIAL", "SYMBOL", "SYMBOL_FUNCTION_CALL"))</pre>
+                      <pre class="language-r">#'  and value is the new variable label; use `NA` to remove label from variable</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">303</td>
+                    <td class="num">15</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">304</td>
-                    <td class="coverage">177<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">16</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      if (length(sym_cond) == 0) {</pre>
+                      <pre class="language-r">#' @return</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">305</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">17</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        return(character(0L))</pre>
+                      <pre class="language-r">#' For `col_labels`, named character vector of variable labels, the names being the corresponding variable names.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">306</td>
+                    <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r">#' If the `label` attribute is missing, the vector elements will be</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">307</td>
+                    <td class="num">19</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      # Watch out for SYMBOLS after $ and @. For x$a x@a: x is object, a is not.</pre>
+                      <pre class="language-r">#' the variable names themselves if `fill = TRUE` and `NA` if `fill = FALSE`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">308</td>
+                    <td class="num">20</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      # For x$a, a's ID is $'s ID-2 so we need to remove all IDs that have ID = $ID - 2.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">309</td>
-                    <td class="coverage">173<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">21</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      dollar_ids &lt;- x[x$token %in% c("'$'", "'@'"), "id"]</pre>
+                      <pre class="language-r">#' For `col_labels&lt;-` and `col_relabel`, copy of `x` with variable labels modified.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">310</td>
-                    <td class="coverage">173<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">22</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      if (length(dollar_ids)) {</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">311</td>
-                    <td class="coverage">12<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">23</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        object_ids &lt;- x[sym_cond, "id"]</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">312</td>
-                    <td class="coverage">12<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">24</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        after_dollar &lt;- object_ids[(object_ids - 2) %in% dollar_ids]</pre>
+                      <pre class="language-r">#' x &lt;- iris</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">313</td>
-                    <td class="coverage">12<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">25</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        sym_cond &lt;- setdiff(sym_cond, which(x$id %in% after_dollar))</pre>
+                      <pre class="language-r">#' col_labels(x)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">314</td>
+                    <td class="num">26</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r">#' col_labels(x) &lt;- paste("label for", names(iris))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">315</td>
+                    <td class="num">27</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' col_labels(x)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">316</td>
-                    <td class="coverage">173<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">28</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      ass_cond &lt;- grep("ASSIGN", x$token)</pre>
+                      <pre class="language-r">#' y &lt;- col_relabel(x, Sepal.Length = "Sepal Length of iris flower")</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">317</td>
-                    <td class="coverage">173<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">29</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      if (!length(ass_cond)) {</pre>
+                      <pre class="language-r">#' col_labels(y)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">318</td>
-                    <td class="coverage">19<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">30</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        return(c("&lt;-", unique(x[sym_cond, "text"])))</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">319</td>
+                    <td class="num">31</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r">#' @source These functions were taken from</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">320</td>
+                    <td class="num">32</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' [formatters](https://cran.r-project.org/package=formatters) package, to reduce the complexity of</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">321</td>
-                    <td class="coverage">154<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">33</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      sym_cond &lt;- sym_cond[sym_cond &gt; ass_cond] # NOTE 1</pre>
+                      <pre class="language-r">#' the dependency tree and rewritten.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">322</td>
+                    <td class="num">34</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      # If there was an assignment operation detect direction of it.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">323</td>
-                    <td class="coverage">154<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">35</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      if (unique(x$text[ass_cond]) == "-&gt;") { # NOTE 2</pre>
+                      <pre class="language-r">#' @rdname col_labels</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">324</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">36</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        sym_cond &lt;- rev(sym_cond)</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">325</td>
+                    <td class="num">37</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">326</td>
+                    <td class="num">38</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">col_labels &lt;- function(x, fill = FALSE) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">327</td>
-                    <td class="coverage">154<em>x</em></td>
+                    <td class="num">39</td>
+                    <td class="coverage">16<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      after &lt;- match(min(x$id[ass_cond]), sort(x$id[c(min(ass_cond), sym_cond)])) - 1</pre>
+                      <pre class="language-r">  checkmate::test_multi_class(x, c("data.frame", "DataFrame"))</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">328</td>
-                    <td class="coverage">154<em>x</em></td>
+                    <td class="num">40</td>
+                    <td class="coverage">16<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      ans &lt;- append(x[sym_cond, "text"], "&lt;-", after = max(1, after))</pre>
+                      <pre class="language-r">  checkmate::assert_flag(fill)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">329</td>
-                    <td class="coverage">154<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">41</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      roll &lt;- in_parenthesis(call_pd)</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">330</td>
-                    <td class="coverage">154<em>x</em></td>
+                    <td class="num">42</td>
+                    <td class="coverage">16<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      if (length(roll)) {</pre>
+                      <pre class="language-r">  if (ncol(x) == 0L) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">331</td>
+                    <td class="num">43</td>
                     <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        c(setdiff(ans, roll), roll)</pre>
+                      <pre class="language-r">    return(character(0L))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">332</td>
+                    <td class="num">44</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      } else {</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">333</td>
-                    <td class="coverage">152<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">45</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        ans</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">334</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">46</td>
+                    <td class="coverage">14<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r">  labels &lt;- sapply(x, function(i) as.vector(attr(i, "label", exact = TRUE)), simplify = FALSE, USE.NAMES = TRUE)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">335</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">47</td>
+                    <td class="coverage">14<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">  mapply(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">336</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">48</td>
+                    <td class="coverage">14<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      ### NOTE 2: What if there are 2 assignments: e.g. a &lt;- b -&gt; c.</pre>
+                      <pre class="language-r">    function(name, label) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">337</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">49</td>
+                    <td class="coverage">62<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      ### NOTE 1: For cases like 'eval(expression(b &lt;- b + 2))' removes 'eval(expression('.</pre>
+                      <pre class="language-r">      checkmate::assert_string(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">338</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">50</td>
+                    <td class="coverage">62<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">        label,</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">339</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">51</td>
+                    <td class="coverage">62<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
+                      <pre class="language-r">        .var.name = sprintf("\"label\" attribute of column \"%s\"", name),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">340</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">52</td>
+                    <td class="coverage">62<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">        null.ok = TRUE</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">341</td>
+                    <td class="num">53</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">      )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">342</td>
+                    <td class="num">54</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Extract side effects</pre>
+                      <pre class="language-r">    },</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">343</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">55</td>
+                    <td class="coverage">14<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    name = names(x),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">344</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">56</td>
+                    <td class="coverage">14<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Extracts all object names from the code that are marked with `@linksto` tag.</pre>
+                      <pre class="language-r">    label = labels</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">345</td>
+                    <td class="num">57</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">346</td>
+                    <td class="num">58</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' The code may contain functions calls that create side effects, e.g. modify the environment.</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">347</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">59</td>
+                    <td class="coverage">12<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Static code analysis may be insufficient to determine which objects are created or modified by such a function call.</pre>
+                      <pre class="language-r">  nulls &lt;- vapply(labels, is.null, logical(1L))</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">348</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">60</td>
+                    <td class="coverage">12<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' The `@linksto` comment tag is introduced to mark a call as having a (side) effect on one or more objects.</pre>
+                      <pre class="language-r">  if (any(nulls)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">349</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">61</td>
+                    <td class="coverage">7<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' With this tag a complete object dependency structure can be established.</pre>
+                      <pre class="language-r">    labels[nulls] &lt;-</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">350</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">62</td>
+                    <td class="coverage">7<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Read more about side effects and the usage of `@linksto` tag in [`get_code_dependencies()`] function.</pre>
+                      <pre class="language-r">      if (fill) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">351</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">63</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">        colnames(x)[nulls]</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">352</td>
+                    <td class="num">64</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param calls_pd `list` of `data.frame`s;</pre>
+                      <pre class="language-r">      } else {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">353</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">65</td>
+                    <td class="coverage">7<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  result of `utils::getParseData()` split into subsets representing individual calls;</pre>
+                      <pre class="language-r">        NA_character_</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">354</td>
+                    <td class="num">66</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  created by `extract_calls()` function</pre>
+                      <pre class="language-r">      }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">355</td>
+                    <td class="num">67</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">356</td>
+                    <td class="num">68</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">357</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">69</td>
+                    <td class="coverage">12<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' A list of length equal to that of `calls_pd`, where each element is a character vector of names of objects</pre>
+                      <pre class="language-r">  unlist(labels)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">358</td>
+                    <td class="num">70</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' depending a call tagged with `@linksto` in a corresponding element of `calls_pd`.</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">359</td>
+                    <td class="num">71</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">360</td>
+                    <td class="num">72</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">#' @rdname col_labels</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">361</td>
+                    <td class="num">73</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">362</td>
+                    <td class="num">74</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">extract_side_effects &lt;- function(calls_pd) {</pre>
+                      <pre class="language-r">`col_labels&lt;-` &lt;- function(x, value) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">363</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">75</td>
+                    <td class="coverage">13<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  lapply(</pre>
+                      <pre class="language-r">  checkmate::test_multi_class(x, c("data.frame", "DataFrame"))</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">364</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">76</td>
+                    <td class="coverage">13<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    calls_pd,</pre>
+                      <pre class="language-r">  checkmate::assert_character(value)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">365</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">77</td>
+                    <td class="coverage">12<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    function(x) {</pre>
+                      <pre class="language-r">  checkmate::assert_true(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">366</td>
-                    <td class="coverage">191<em>x</em></td>
+                    <td class="num">78</td>
+                    <td class="coverage">12<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      linksto &lt;- grep("@linksto", x[x$token == "COMMENT", "text"], value = TRUE)</pre>
+                      <pre class="language-r">    ncol(x) == length(value),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">367</td>
-                    <td class="coverage">191<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      unlist(strsplit(sub("\\s*#\\s*@linksto\\s+", "", linksto), "\\s+"))</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">368</td>
-                    <td class="coverage"></td>
+                    <td class="num">79</td>
+                    <td class="coverage">12<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">    .var.name = "Length of value is equal to the number of columns"</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">369</td>
+                    <td class="num">80</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">  )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">370</td>
+                    <td class="num">81</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">371</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">82</td>
+                    <td class="coverage">11<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">  varnames &lt;-</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">372</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">83</td>
+                    <td class="coverage">11<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"># graph_parser ----</pre>
+                      <pre class="language-r">    if (is.null(names(value))) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">373</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">84</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">      names(x)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">374</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">85</td>
+                    <td class="coverage">11<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Return the indices of calls needed to reproduce an object</pre>
+                      <pre class="language-r">    } else if (any(names(value) == "")) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">375</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">86</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      specified_cols &lt;- names(value)[names(value) != ""]</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">376</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">87</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param x The name of the object to return code for.</pre>
+                      <pre class="language-r">      checkmate::assert_subset(specified_cols, names(x), .var.name = "names of value")</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">377</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">88</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param graph A result of `code_graph()`.</pre>
+                      <pre class="language-r">      res &lt;- names(value)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">378</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">89</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      res[res == ""] &lt;- setdiff(names(x), specified_cols)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">379</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">90</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return</pre>
+                      <pre class="language-r">      res</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">380</td>
+                    <td class="num">91</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Integer vector of indices that can be applied to `graph` to obtain all calls required to reproduce object `x`.</pre>
+                      <pre class="language-r">    } else {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">381</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">92</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      checkmate::assert_set_equal(names(value), names(x), .var.name = "names of value")</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">382</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">93</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">      names(value)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">383</td>
+                    <td class="num">94</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">384</td>
+                    <td class="num">95</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">graph_parser &lt;- function(x, graph) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">385</td>
-                    <td class="coverage">244<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  occurrence &lt;- vapply(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">386</td>
-                    <td class="coverage">244<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    graph,</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">387</td>
-                    <td class="coverage">244<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    function(call) {</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">388</td>
-                    <td class="coverage">652<em>x</em></td>
+                    <td class="num">96</td>
+                    <td class="coverage">10<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      ind &lt;- match("&lt;-", call, nomatch = length(call) + 1L)</pre>
+                      <pre class="language-r">  for (i in seq_along(value)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">389</td>
-                    <td class="coverage">652<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      x %in% call[seq_len(ind - 1L)]</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">390</td>
-                    <td class="coverage"></td>
+                    <td class="num">97</td>
+                    <td class="coverage">40<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    },</pre>
+                      <pre class="language-r">    if (is.na(value[i])) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">391</td>
-                    <td class="coverage">244<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    logical(1)</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">392</td>
-                    <td class="coverage"></td>
+                    <td class="num">98</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
+                      <pre class="language-r">      attr(x[[varnames[i]]], "label") &lt;- NULL</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">393</td>
+                    <td class="num">99</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">394</td>
-                    <td class="coverage">244<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  dependencies &lt;- lapply(graph[occurrence], function(call) {</pre>
+                      <pre class="language-r">    } else {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">395</td>
-                    <td class="coverage">122<em>x</em></td>
+                    <td class="num">100</td>
+                    <td class="coverage">38<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    ind &lt;- match("&lt;-", call, nomatch = 0L)</pre>
+                      <pre class="language-r">      attr(x[[varnames[i]]], "label") &lt;- value[[i]]</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">396</td>
-                    <td class="coverage">122<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">101</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    call[(ind + 1L):length(call)]</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">397</td>
+                    <td class="num">102</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  })</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">398</td>
-                    <td class="coverage">244<em>x</em></td>
+                    <td class="num">103</td>
+                    <td class="coverage">10<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  dependencies &lt;- setdiff(unlist(dependencies), x)</pre>
+                      <pre class="language-r">  x</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">399</td>
+                    <td class="num">104</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">400</td>
-                    <td class="coverage">244<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">105</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (length(dependencies) &amp;&amp; any(occurrence)) {</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">401</td>
-                    <td class="coverage">91<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">106</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    dependency_ids &lt;- lapply(dependencies, function(dependency) {</pre>
+                      <pre class="language-r">#' @rdname col_labels</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">402</td>
-                    <td class="coverage">185<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">107</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      graph_parser(dependency, graph[1:max(which(occurrence))])</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">403</td>
+                    <td class="num">108</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    })</pre>
+                      <pre class="language-r">col_relabel &lt;- function(x, ...) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">404</td>
-                    <td class="coverage">91<em>x</em></td>
+                    <td class="num">109</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    sort(unique(c(which(occurrence), unlist(dependency_ids))))</pre>
+                      <pre class="language-r">  checkmate::test_multi_class(x, c("data.frame", "DataFrame"))</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">405</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">110</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else {</pre>
+                      <pre class="language-r">  if (missing(...)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">406</td>
-                    <td class="coverage">153<em>x</em></td>
+                    <td class="num">111</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    which(occurrence)</pre>
+                      <pre class="language-r">    return(x)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">407</td>
+                    <td class="num">112</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">408</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">113</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">  value &lt;- list(...)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">409</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">114</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">  varnames &lt;- names(value)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">410</td>
+                    <td class="num">115</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">411</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">116</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"># default_side_effects --------------------------------------------------------------------------------------------</pre>
+                      <pre class="language-r">  checkmate::assert_subset(varnames, names(x), .var.name = "names of ...")</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">412</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">117</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">  lapply(value, checkmate::assert_string, .var.name = "element of ...", na.ok = TRUE)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">413</td>
+                    <td class="num">118</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Detect library calls</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">414</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">119</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  for (i in seq_along(value)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">415</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">120</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Detects `library()` and `require()` function calls.</pre>
+                      <pre class="language-r">    if (is.na(value[i])) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">416</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">121</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      attr(x[[varnames[i]]], "label") &lt;- NULL</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">417</td>
+                    <td class="num">122</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param calls_pd `list` of `data.frame`s;</pre>
+                      <pre class="language-r">    } else {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">418</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">123</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  result of `utils::getParseData()` split into subsets representing individual calls;</pre>
+                      <pre class="language-r">      attr(x[[varnames[i]]], "label") &lt;- value[[i]]</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">419</td>
+                    <td class="num">124</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'  created by `extract_calls()` function</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">420</td>
+                    <td class="num">125</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">421</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">126</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return</pre>
+                      <pre class="language-r">  x</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">422</td>
+                    <td class="num">127</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Integer vector of indices that can be applied to `graph` (result of `code_graph()`) to obtain all calls containing</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
+                </tbody>
+              </table>
+            </div>
+            <div id="R/join_keys-names.R" class="hidden">
+              <table class="table-condensed">
+                <tbody>
                   <tr class="never">
-                    <td class="num">423</td>
+                    <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' `library()` or `require()` calls that are always returned for reproducibility.</pre>
+                      <pre class="language-r">#' The names of a `join_keys` object</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">424</td>
+                    <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">425</td>
+                    <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">#' @inheritParams base::`names&lt;-`</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">426</td>
+                    <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">427</td>
+                    <td class="num">5</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">detect_libraries &lt;- function(calls_pd) {</pre>
+                      <pre class="language-r">`names&lt;-.join_keys` &lt;- function(x, value) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">428</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">6</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  defaults &lt;- c("library", "require")</pre>
+                      <pre class="language-r">  new_x &lt;- unclass(x)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">429</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">7</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">  parent_list &lt;- parents(x)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">430</td>
-                    <td class="coverage">58<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">8</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  which(</pre>
+                      <pre class="language-r">  # Update inner keys</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">431</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">9</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    vapply(</pre>
+                      <pre class="language-r">  for (old_name in setdiff(names(new_x), value)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">432</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">10</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      calls_pd,</pre>
+                      <pre class="language-r">    old_entry &lt;- new_x[[old_name]]</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">433</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">11</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      function(call) {</pre>
+                      <pre class="language-r">    new_name &lt;- value[names(new_x) == old_name]</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">434</td>
-                    <td class="coverage">191<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">12</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        any(call$token == "SYMBOL_FUNCTION_CALL" &amp; call$text %in% defaults)</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">435</td>
+                    <td class="num">13</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      },</pre>
+                      <pre class="language-r">    # Change 2nd-tier first</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">436</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">14</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      logical(1)</pre>
+                      <pre class="language-r">    for (sub_name in names(old_entry)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">437</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">15</td>
+                    <td class="coverage">7<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    )</pre>
+                      <pre class="language-r">      names(new_x[[sub_name]])[names(new_x[[sub_name]]) == old_name] &lt;- new_name</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">438</td>
+                    <td class="num">16</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">439</td>
+                    <td class="num">17</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">440</td>
+                    <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">    # Change in first tier</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">441</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">19</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Normalize parsed data removing backticks from symbols</pre>
+                      <pre class="language-r">    names(new_x)[names(new_x) == old_name] &lt;- new_name</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">442</td>
+                    <td class="num">20</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">443</td>
+                    <td class="num">21</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param pd `data.frame` resulting from `utils::getParseData()` call.</pre>
+                      <pre class="language-r">    # changing name in the parents</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">444</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">22</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    if (length(parent_list)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">445</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">23</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return `data.frame` with backticks removed from `text` column for `SYMBOL` tokens.</pre>
+                      <pre class="language-r">      names(parent_list)[names(parent_list) == old_name] &lt;- new_name</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">446</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">24</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      ind &lt;- vapply(parent_list, identical, logical(1), old_name)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">447</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">25</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">      parent_list[ind] &lt;- new_name</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">448</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">26</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @noRd</pre>
+                      <pre class="language-r">      attr(new_x, "parents") &lt;- parent_list</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">449</td>
+                    <td class="num">27</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">normalize_pd &lt;- function(pd) {</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">450</td>
+                    <td class="num">28</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # Remove backticks from SYMBOL tokens</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">451</td>
-                    <td class="coverage">58<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  symbol_index &lt;- grepl("^SYMBOL.*$", pd$token)</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">452</td>
-                    <td class="coverage">58<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  pd[symbol_index, "text"] &lt;- gsub("^`(.*)`$", "\\1", pd[symbol_index, "text"])</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">453</td>
+                    <td class="num">29</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">454</td>
-                    <td class="coverage">58<em>x</em></td>
+                    <td class="num">30</td>
+                    <td class="coverage">2<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  class(new_x) &lt;- c("join_keys", "list")</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">31</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  pd</pre>
+                      <pre class="language-r">  new_x</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">455</td>
+                    <td class="num">32</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">}</pre>
@@ -12129,14 +8741,14 @@ <h2>teal.data coverage - 89.08%</h2>
                 </tbody>
               </table>
             </div>
-            <div id="R/testhat-helpers.R" class="hidden">
+            <div id="R/topological_sort.R" class="hidden">
               <table class="table-condensed">
                 <tbody>
                   <tr class="never">
                     <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Test if two objects are (nearly) equal</pre>
+                      <pre class="language-r">#' Topological graph sort</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -12150,14 +8762,14 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' `all.equal(target, current)` is a utility to compare `join_keys` objects target</pre>
+                      <pre class="language-r">#' Graph is a `list` which for each node contains a vector of child nodes</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' and current testing `near equality`.</pre>
+                      <pre class="language-r">#' in the returned list, parents appear before their children.</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -12171,347 +8783,410 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">6</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' If they are different, comparison is still made to some extent, and a report</pre>
+                      <pre class="language-r">#' Implementation of `Kahn` algorithm with a modification to maintain the order of input elements.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">7</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' of the differences is returned.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">8</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Do not use `all.equal` directly in if expressions—either use `isTRUE(all.equal(....))`</pre>
+                      <pre class="language-r">#' @param graph (`named list`) with node vector elements</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">9</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' or identical if appropriate.</pre>
+                      <pre class="language-r">#' @keywords internal</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">10</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">topological_sort &lt;- function(graph) {</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">11</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' The parents attribute comparison tolerates `NULL` and empty lists and will find</pre>
+                      <pre class="language-r">  # compute in-degrees</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">12</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">498<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' no difference.</pre>
+                      <pre class="language-r">  in_degrees &lt;- list()</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">13</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">498<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  for (node in names(graph)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">14</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">231<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' The list containing all the relationships is treated like a map and ignores</pre>
+                      <pre class="language-r">    in_degrees[[node]] &lt;- 0</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">15</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">231<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' entries with `NULL` if they exist.</pre>
+                      <pre class="language-r">    for (to_edge in graph[[node]]) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">16</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">184<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      in_degrees[[to_edge]] &lt;- 0</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">17</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @inheritParams base::all.equal</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param ... further arguments for different methods. Not used with `join_keys`.</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">19</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">20</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">498<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @seealso [base::all.equal()]</pre>
+                      <pre class="language-r">  for (node in graph) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">21</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">231<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">    for (to_edge in node) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">22</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">184<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      in_degrees[[to_edge]] &lt;- in_degrees[[to_edge]] + 1</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">23</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">all.equal.join_keys &lt;- function(target, current, ...) {</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">24</td>
-                    <td class="coverage">21<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  .as_map &lt;- function(.x) {</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">25</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    old_attributes &lt;- attributes(.x)</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">26</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # Keep only non-list attributes</pre>
+                      <pre class="language-r">  # sort</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">27</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage">498<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    old_attributes[["names"]] &lt;- NULL</pre>
+                      <pre class="language-r">  visited &lt;- 0</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">28</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage">498<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    old_attributes[["original_class"]] &lt;- old_attributes[["class"]]</pre>
+                      <pre class="language-r">  sorted &lt;- list()</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">29</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage">498<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    old_attributes[["class"]] &lt;- NULL</pre>
+                      <pre class="language-r">  zero_in &lt;- list()</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">30</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage">498<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    old_attributes[["parents"]] &lt;- if (!length(old_attributes[["parents"]])) {</pre>
+                      <pre class="language-r">  for (node in names(in_degrees)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">31</td>
-                    <td class="coverage">18<em>x</em></td>
+                    <td class="coverage">200<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      list()</pre>
+                      <pre class="language-r">    if (in_degrees[[node]] == 0) zero_in &lt;- append(zero_in, node)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">32</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    } else {</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">33</td>
-                    <td class="coverage">24<em>x</em></td>
+                    <td class="coverage">498<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      old_attributes[["parents"]][order(names(old_attributes[["parents"]]))]</pre>
+                      <pre class="language-r">  zero_in &lt;- rev(zero_in)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">34</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">35</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage">498<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    attr(.x, "class") &lt;- "list"</pre>
+                      <pre class="language-r">  while (length(zero_in) != 0) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">36</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">357<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">    visited &lt;- visited + 1</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">37</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">357<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # Remove nulls</pre>
+                      <pre class="language-r">    sorted &lt;- c(zero_in[[1]], sorted)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">38</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage">357<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    .x &lt;- Filter(Negate(is.null), .x)</pre>
+                      <pre class="language-r">    for (edge_to in graph[[zero_in[[1]]]]) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">39</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">176<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">      in_degrees[[edge_to]] &lt;- in_degrees[[edge_to]] - 1</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">40</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">176<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # Sort named components, preserving positions of unnamed</pre>
+                      <pre class="language-r">      if (in_degrees[[edge_to]] == 0) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">41</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage">157<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    nx &lt;- rlang::names2(.x)</pre>
+                      <pre class="language-r">        zero_in &lt;- append(zero_in, edge_to, 1)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">42</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    is_named &lt;- nx != ""</pre>
+                      <pre class="language-r">      }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">43</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (any(is_named)) {</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">44</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage">357<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      idx &lt;- seq_along(.x)</pre>
+                      <pre class="language-r">    zero_in[[1]] &lt;- NULL</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">45</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      idx[is_named] &lt;- idx[is_named][order(nx[is_named])]</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">46</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      .x &lt;- .x[idx]</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">47</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">498<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">  if (visited != length(in_degrees)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">48</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    new_attributes &lt;- if (is.null(attributes(.x))) list() else attributes(.x)</pre>
+                      <pre class="language-r">    stop(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">49</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    attributes(.x) &lt;- utils::modifyList(old_attributes, new_attributes)</pre>
+                      <pre class="language-r">      "Graph is not a directed acyclic graph. Cycles involving nodes: ",</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">50</td>
-                    <td class="coverage">42<em>x</em></td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    .x</pre>
+                      <pre class="language-r">      paste0(setdiff(names(in_degrees), sorted), collapse = " ")</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">51</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">    )</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">52</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  } else {</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">53</td>
+                    <td class="coverage">494<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">    return(sorted)</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">54</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  }</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">55</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">}</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">56</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r"></pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">57</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#' Checks whether a graph is a `Directed Acyclic Graph (DAG)`</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">58</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#'</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">59</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#' @inheritParams topological_sort</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">60</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#' @return `logical(1)` `TRUE` if the graph is a `DAG`; `FALSE` otherwise</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">52</td>
-                    <td class="coverage">21<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">61</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x &lt;- .as_map(target)</pre>
+                      <pre class="language-r">#' @keywords internal</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">53</td>
-                    <td class="coverage">21<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">62</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  y &lt;- .as_map(current)</pre>
+                      <pre class="language-r">is_dag &lt;- function(graph) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">54</td>
-                    <td class="coverage">21<em>x</em></td>
+                    <td class="num">63</td>
+                    <td class="coverage">433<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  all.equal(x, y)</pre>
+                      <pre class="language-r">  inherits(try(topological_sort(graph), silent = TRUE), "try-error")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">55</td>
+                    <td class="num">64</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">}</pre>
@@ -12520,1942 +9195,1958 @@ <h2>teal.data coverage - 89.08%</h2>
                 </tbody>
               </table>
             </div>
-            <div id="R/join_keys-names.R" class="hidden">
+            <div id="R/join_keys.R" class="hidden">
               <table class="table-condensed">
                 <tbody>
                   <tr class="never">
                     <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' The names of a `join_keys` object</pre>
+                      <pre class="language-r">#' Manage relationships between datasets using `join_keys`</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @order 1</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @inheritParams base::`names&lt;-`</pre>
+                      <pre class="language-r">#' @name join_keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">5</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">`names&lt;-.join_keys` &lt;- function(x, value) {</pre>
+                      <pre class="language-r">#' @usage ## Constructor, getter and setter</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">6</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  new_x &lt;- unclass(x)</pre>
+                      <pre class="language-r">#' join_keys(...)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">7</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  parent_list &lt;- parents(x)</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">8</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # Update inner keys</pre>
+                      <pre class="language-r">#' @description</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">9</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  for (old_name in setdiff(names(new_x), value)) {</pre>
+                      <pre class="language-r">#' Facilitates the creation and retrieval of relationships between datasets.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">10</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    old_entry &lt;- new_x[[old_name]]</pre>
+                      <pre class="language-r">#' `join_keys` class extends `list` and contains keys connecting pairs of datasets.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">11</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    new_name &lt;- value[names(new_x) == old_name]</pre>
+                      <pre class="language-r">#' Each element of the list contains keys for specific dataset.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">12</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' Each dataset can have a relationship with itself (primary key) and with other datasets.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">13</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # Change 2nd-tier first</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">14</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    for (sub_name in names(old_entry)) {</pre>
+                      <pre class="language-r">#' Note that `join_keys` list is symmetrical and assumes a default direction, that is:</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">15</td>
-                    <td class="coverage">7<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      names(new_x[[sub_name]])[names(new_x[[sub_name]]) == old_name] &lt;- new_name</pre>
+                      <pre class="language-r">#' when keys are set between `ds1` and `ds2`, it defines `ds1` as the parent</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">16</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#' in a parent-child relationship and the mapping is automatically mirrored between</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">17</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' `ds2` and `ds1`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # Change in first tier</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">19</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    names(new_x)[names(new_x) == old_name] &lt;- new_name</pre>
+                      <pre class="language-r">#' @section Methods (by class):</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">20</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' - `join_keys()`: Returns an empty `join_keys` object when called without arguments.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">21</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # changing name in the parents</pre>
+                      <pre class="language-r">#' - `join_keys(join_keys)`: Returns itself.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">22</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (length(parent_list)) {</pre>
+                      <pre class="language-r">#' - `join_keys(teal_data)`: Returns the `join_keys` object contained in `teal_data` object.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">23</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      names(parent_list)[names(parent_list) == old_name] &lt;- new_name</pre>
+                      <pre class="language-r">#' - `join_keys(...)`: Creates a new object with one or more `join_key_set` parameters.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">24</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      ind &lt;- vapply(parent_list, identical, logical(1), old_name)</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">25</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      parent_list[ind] &lt;- new_name</pre>
+                      <pre class="language-r">#' @param ... optional,</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">26</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      attr(new_x, "parents") &lt;- parent_list</pre>
+                      <pre class="language-r">#' - either `teal_data` or `join_keys` object to extract `join_keys`</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">27</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#' - or any number of `join_key_set` objects to create `join_keys`</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">28</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' - or nothing to create an empty `join_keys`</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">29</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @param value For `x[i, j, directed = TRUE)] &lt;- value` (named/unnamed `character`)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">30</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  class(new_x) &lt;- c("join_keys", "list")</pre>
+                      <pre class="language-r">#' Column mapping between datasets.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">31</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  new_x</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">32</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#' For `join_keys(x) &lt;- value`: (`join_key_set` or list of `join_key_set`) relationship</pre>
                     </td>
                   </tr>
-                </tbody>
-              </table>
-            </div>
-            <div id="R/topological_sort.R" class="hidden">
-              <table class="table-condensed">
-                <tbody>
                   <tr class="never">
-                    <td class="num">1</td>
+                    <td class="num">33</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Topological graph sort</pre>
+                      <pre class="language-r">#' pairs to add to `join_keys` list.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">2</td>
+                    <td class="num">34</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">3</td>
+                    <td class="num">35</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Graph is a `list` which for each node contains a vector of child nodes</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">4</td>
+                    <td class="num">36</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' in the returned list, parents appear before their children.</pre>
+                      <pre class="language-r">#' @return `join_keys` object.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">5</td>
+                    <td class="num">37</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">6</td>
+                    <td class="num">38</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Implementation of `Kahn` algorithm with a modification to maintain the order of input elements.</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">7</td>
+                    <td class="num">39</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' # Creating a new join keys ----</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">8</td>
+                    <td class="num">40</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param graph (`named list`) with node vector elements</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">9</td>
+                    <td class="num">41</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">#' jk &lt;- join_keys(</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">10</td>
+                    <td class="num">42</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">topological_sort &lt;- function(graph) {</pre>
+                      <pre class="language-r">#'   join_key("ds1", "ds1", "pk1"),</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">11</td>
+                    <td class="num">43</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # compute in-degrees</pre>
+                      <pre class="language-r">#'   join_key("ds2", "ds2", "pk2"),</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">12</td>
-                    <td class="coverage">547<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">44</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  in_degrees &lt;- list()</pre>
+                      <pre class="language-r">#'   join_key("ds3", "ds3", "pk3"),</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">13</td>
-                    <td class="coverage">547<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">45</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  for (node in names(graph)) {</pre>
+                      <pre class="language-r">#'   join_key("ds1", "ds2", c(pk1 = "pk2")),</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">14</td>
-                    <td class="coverage">241<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">46</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    in_degrees[[node]] &lt;- 0</pre>
+                      <pre class="language-r">#'   join_key("ds1", "ds3", c(pk1 = "pk3"))</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">15</td>
-                    <td class="coverage">241<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">47</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    for (to_edge in graph[[node]]) {</pre>
+                      <pre class="language-r">#' )</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">16</td>
-                    <td class="coverage">184<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">48</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      in_degrees[[to_edge]] &lt;- 0</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">17</td>
+                    <td class="num">49</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#' jk</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">18</td>
+                    <td class="num">50</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">19</td>
+                    <td class="num">51</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">20</td>
-                    <td class="coverage">547<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">52</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  for (node in graph) {</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">21</td>
-                    <td class="coverage">241<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">53</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    for (to_edge in node) {</pre>
+                      <pre class="language-r">#' @seealso [join_key()] for creating `join_keys_set`,</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">22</td>
-                    <td class="coverage">184<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">54</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      in_degrees[[to_edge]] &lt;- in_degrees[[to_edge]] + 1</pre>
+                      <pre class="language-r">#' [parents()] for parent operations,</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">23</td>
+                    <td class="num">55</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#' [teal_data()] for `teal_data` constructor _and_</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">24</td>
+                    <td class="num">56</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' [default_cdisc_join_keys] for default CDISC keys.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">25</td>
+                    <td class="num">57</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">26</td>
+                    <td class="num">58</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # sort</pre>
+                      <pre class="language-r">join_keys &lt;- function(...) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">27</td>
-                    <td class="coverage">547<em>x</em></td>
+                    <td class="num">59</td>
+                    <td class="coverage">771<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  visited &lt;- 0</pre>
+                      <pre class="language-r">  if (missing(...)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">28</td>
-                    <td class="coverage">547<em>x</em></td>
+                    <td class="num">60</td>
+                    <td class="coverage">196<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  sorted &lt;- list()</pre>
+                      <pre class="language-r">    return(new_join_keys())</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">61</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">29</td>
-                    <td class="coverage">547<em>x</em></td>
+                    <td class="num">62</td>
+                    <td class="coverage">575<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  zero_in &lt;- list()</pre>
+                      <pre class="language-r">  x &lt;- rlang::list2(...)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">30</td>
-                    <td class="coverage">547<em>x</em></td>
+                    <td class="num">63</td>
+                    <td class="coverage">575<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  for (node in names(in_degrees)) {</pre>
+                      <pre class="language-r">  if (length(x) == 1L) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">31</td>
-                    <td class="coverage">210<em>x</em></td>
+                    <td class="num">64</td>
+                    <td class="coverage">510<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (in_degrees[[node]] == 0) zero_in &lt;- append(zero_in, node)</pre>
+                      <pre class="language-r">    UseMethod("join_keys", x[[1]])</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">32</td>
+                    <td class="num">65</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">  } else {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">33</td>
-                    <td class="coverage">547<em>x</em></td>
+                    <td class="num">66</td>
+                    <td class="coverage">65<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  zero_in &lt;- rev(zero_in)</pre>
+                      <pre class="language-r">    join_keys.default(...)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">34</td>
+                    <td class="num">67</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">35</td>
-                    <td class="coverage">547<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">68</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  while (length(zero_in) != 0) {</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">36</td>
-                    <td class="coverage">367<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">69</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    visited &lt;- visited + 1</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">37</td>
-                    <td class="coverage">367<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">70</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    sorted &lt;- c(zero_in[[1]], sorted)</pre>
+                      <pre class="language-r">#' @rdname join_keys</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">38</td>
-                    <td class="coverage">367<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">71</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    for (edge_to in graph[[zero_in[[1]]]]) {</pre>
+                      <pre class="language-r">#' @order 1</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">39</td>
-                    <td class="coverage">176<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">72</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      in_degrees[[edge_to]] &lt;- in_degrees[[edge_to]] - 1</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">40</td>
-                    <td class="coverage">176<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">73</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      if (in_degrees[[edge_to]] == 0) {</pre>
+                      <pre class="language-r">join_keys.default &lt;- function(...) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">41</td>
-                    <td class="coverage">157<em>x</em></td>
+                    <td class="num">74</td>
+                    <td class="coverage">113<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        zero_in &lt;- append(zero_in, edge_to, 1)</pre>
+                      <pre class="language-r">  c(new_join_keys(), ...)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">42</td>
+                    <td class="num">75</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">43</td>
+                    <td class="num">76</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">44</td>
-                    <td class="coverage">367<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">77</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    zero_in[[1]] &lt;- NULL</pre>
+                      <pre class="language-r">#' @rdname join_keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">45</td>
+                    <td class="num">78</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' @order 1</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">46</td>
+                    <td class="num">79</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">47</td>
-                    <td class="coverage">547<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">80</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (visited != length(in_degrees)) {</pre>
+                      <pre class="language-r">join_keys.join_keys &lt;- function(...) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">48</td>
-                    <td class="coverage">4<em>x</em></td>
+                    <td class="num">81</td>
+                    <td class="coverage">457<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    stop(</pre>
+                      <pre class="language-r">  x &lt;- rlang::list2(...)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">49</td>
-                    <td class="coverage">4<em>x</em></td>
+                    <td class="num">82</td>
+                    <td class="coverage">457<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      "Graph is not a directed acyclic graph. Cycles involving nodes: ",</pre>
+                      <pre class="language-r">  x[[1]]</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">50</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">83</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      paste0(setdiff(names(in_degrees), sorted), collapse = " ")</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">51</td>
+                    <td class="num">84</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    )</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">52</td>
+                    <td class="num">85</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else {</pre>
+                      <pre class="language-r">#' @rdname join_keys</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">53</td>
-                    <td class="coverage">543<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">86</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    return(sorted)</pre>
+                      <pre class="language-r">#' @order 1</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">54</td>
+                    <td class="num">87</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">55</td>
+                    <td class="num">88</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">join_keys.teal_data &lt;- function(...) {</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">89</td>
+                    <td class="coverage">5<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  x &lt;- rlang::list2(...)</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">90</td>
+                    <td class="coverage">5<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  x[[1]]@join_keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">56</td>
+                    <td class="num">91</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">57</td>
+                    <td class="num">92</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Checks whether a graph is a `Directed Acyclic Graph (DAG)`</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">58</td>
+                    <td class="num">93</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @rdname join_keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">59</td>
+                    <td class="num">94</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @inheritParams topological_sort</pre>
+                      <pre class="language-r">#' @order 5</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">60</td>
+                    <td class="num">95</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return `logical(1)` `TRUE` if the graph is a `DAG`; `FALSE` otherwise</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">61</td>
+                    <td class="num">96</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">#' @section Functions:</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">62</td>
+                    <td class="num">97</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">is_dag &lt;- function(graph) {</pre>
+                      <pre class="language-r">#' - `join_keys(x) &lt;- value`: Assignment of the `join_keys` in object with `value`.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">63</td>
-                    <td class="coverage">433<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">98</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  inherits(try(topological_sort(graph), silent = TRUE), "try-error")</pre>
+                      <pre class="language-r">#' `value` needs to be an object of class `join_keys` or `join_key_set`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">64</td>
+                    <td class="num">99</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
-                  </tr>
-                </tbody>
-              </table>
-            </div>
-            <div id="R/teal_data-show.R" class="hidden">
-              <table class="table-condensed">
-                <tbody>
+                  </tr>
                   <tr class="never">
-                    <td class="num">1</td>
+                    <td class="num">100</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Show `teal_data` object</pre>
+                      <pre class="language-r">#' @param x (`join_keys`) empty object to set the new relationship pairs.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">2</td>
+                    <td class="num">101</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' `x` is typically an object of `join_keys` class. When called with the `join_keys(x)`</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">3</td>
+                    <td class="num">102</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Prints `teal_data` object.</pre>
+                      <pre class="language-r">#' or `join_keys(x) &lt;- value` then it can also take a supported class (`teal_data`, `join_keys`)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">4</td>
+                    <td class="num">103</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">5</td>
+                    <td class="num">104</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param object (`teal_data`)</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">6</td>
+                    <td class="num">105</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return Input `teal_data` object.</pre>
+                      <pre class="language-r">`join_keys&lt;-` &lt;- function(x, value) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">7</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">106</td>
+                    <td class="coverage">16<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @importFrom methods show</pre>
+                      <pre class="language-r">  checkmate::assert_class(value, classes = c("join_keys", "list"))</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">107</td>
+                    <td class="coverage">16<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  UseMethod("join_keys&lt;-", x)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">8</td>
+                    <td class="num">108</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">9</td>
+                    <td class="num">109</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' teal_data()</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">10</td>
+                    <td class="num">110</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' teal_data(x = iris, code = "x = iris")</pre>
+                      <pre class="language-r">#' @rdname join_keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">11</td>
+                    <td class="num">111</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' verify(teal_data(x = iris, code = "x = iris"))</pre>
+                      <pre class="language-r">#' @order 5</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">12</td>
+                    <td class="num">112</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">13</td>
+                    <td class="num">113</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">setMethod("show", signature = "teal_data", function(object) {</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
-                  <tr class="missed">
-                    <td class="num">14</td>
-                    <td class="coverage">!</td>
+                  <tr class="never">
+                    <td class="num">114</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (object@verified) {</pre>
+                      <pre class="language-r">#' # Assigning keys via join_keys(x)[i, j] &lt;- value ----</pre>
                     </td>
                   </tr>
-                  <tr class="missed">
-                    <td class="num">15</td>
-                    <td class="coverage">!</td>
+                  <tr class="never">
+                    <td class="num">115</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    cat("\u2705\ufe0e", "verified teal_data object\n")</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">16</td>
+                    <td class="num">116</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else {</pre>
+                      <pre class="language-r">#' obj &lt;- join_keys()</pre>
                     </td>
                   </tr>
-                  <tr class="missed">
-                    <td class="num">17</td>
-                    <td class="coverage">!</td>
+                  <tr class="never">
+                    <td class="num">117</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    cat("\u2716", "unverified teal_data object\n")</pre>
+                      <pre class="language-r">#' # or</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">18</td>
+                    <td class="num">118</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' obj &lt;- teal_data()</pre>
                     </td>
                   </tr>
-                  <tr class="missed">
-                    <td class="num">19</td>
-                    <td class="coverage">!</td>
+                  <tr class="never">
+                    <td class="num">119</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  rlang::env_print(object@env)</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">20</td>
+                    <td class="num">120</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">})</pre>
+                      <pre class="language-r">#' join_keys(obj)["ds1", "ds1"] &lt;- "pk1"</pre>
                     </td>
                   </tr>
-                </tbody>
-              </table>
-            </div>
-            <div id="R/join_keys-utils.R" class="hidden">
-              <table class="table-condensed">
-                <tbody>
                   <tr class="never">
-                    <td class="num">1</td>
+                    <td class="num">121</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Check Compatibility of keys</pre>
+                      <pre class="language-r">#' join_keys(obj)["ds2", "ds2"] &lt;- "pk2"</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">2</td>
+                    <td class="num">122</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' join_keys(obj)["ds3", "ds3"] &lt;- "pk3"</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">3</td>
+                    <td class="num">123</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Helper function to assert if two key sets contain incompatible keys.</pre>
+                      <pre class="language-r">#' join_keys(obj)["ds1", "ds2"] &lt;- c(pk1 = "pk2")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">4</td>
+                    <td class="num">124</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' join_keys(obj)["ds1", "ds3"] &lt;- c(pk1 = "pk3")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">5</td>
+                    <td class="num">125</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return Returns `TRUE` if successful, otherwise raises error.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">6</td>
+                    <td class="num">126</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">#' identical(jk, join_keys(obj))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">7</td>
+                    <td class="num">127</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">assert_compatible_keys &lt;- function(join_key_1, join_key_2) {</pre>
+                      <pre class="language-r">`join_keys&lt;-.join_keys` &lt;- function(x, value) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">8</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="num">128</td>
+                    <td class="coverage">10<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  stop_message &lt;- function(dataset_1, dataset_2) {</pre>
+                      <pre class="language-r">  value</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">9</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">129</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    stop(</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">10</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">130</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      paste("cannot specify multiple different join keys between datasets:", dataset_1, "and", dataset_2)</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">11</td>
+                    <td class="num">131</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    )</pre>
+                      <pre class="language-r">#' @rdname join_keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">12</td>
+                    <td class="num">132</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' @order 5</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">13</td>
+                    <td class="num">133</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">14</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">134</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  dataset_1_one &lt;- names(join_key_1)</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">15</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">135</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  dataset_2_one &lt;- names(join_key_1[[1]])</pre>
+                      <pre class="language-r">#' # Setter for join_keys within teal_data ----</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">16</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">136</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  keys_one &lt;- join_key_1[[1]][[1]]</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">17</td>
+                    <td class="num">137</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' td &lt;- teal_data()</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">18</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">138</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  dataset_1_two &lt;- names(join_key_2)</pre>
+                      <pre class="language-r">#' join_keys(td) &lt;- jk</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">19</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">139</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  dataset_2_two &lt;- names(join_key_2[[1]])</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">20</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">140</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  keys_two &lt;- join_key_2[[1]][[1]]</pre>
+                      <pre class="language-r">#' join_keys(td)["ds1", "ds2"] &lt;- "new_key"</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">21</td>
+                    <td class="num">141</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' join_keys(td) &lt;- c(join_keys(td), join_keys(join_key("ds3", "ds2", "key3")))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">22</td>
+                    <td class="num">142</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # if first datasets and the second datasets match and keys</pre>
+                      <pre class="language-r">#' join_keys(td)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">23</td>
+                    <td class="num">143</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # must contain the same named elements</pre>
+                      <pre class="language-r">`join_keys&lt;-.teal_data` &lt;- function(x, value) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">24</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="num">144</td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (dataset_1_one == dataset_1_two &amp;&amp; dataset_2_one == dataset_2_two) {</pre>
+                      <pre class="language-r">  join_keys(x@join_keys) &lt;- value</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">145</td>
+                    <td class="coverage">6<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  datanames(x) &lt;- x@datanames # datanames fun manages some exceptions</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">146</td>
+                    <td class="coverage">6<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  x</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">25</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">147</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (!identical(sort(keys_one), sort(keys_two))) {</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">26</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">148</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      stop_message(dataset_1_one, dataset_2_one)</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">27</td>
+                    <td class="num">149</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#' Internal constructor</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">28</td>
+                    <td class="num">150</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">29</td>
+                    <td class="num">151</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @return an empty `join_keys` list</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">30</td>
+                    <td class="num">152</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # if first dataset of join_key_1 matches second dataset of join_key_2</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">31</td>
+                    <td class="num">153</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # and the first dataset of join_key_2 must match second dataset of join_key_1</pre>
+                      <pre class="language-r">#' @keywords internal</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">32</td>
+                    <td class="num">154</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # and keys must contain the same elements but with names and values swapped</pre>
+                      <pre class="language-r">new_join_keys &lt;- function() {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">33</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="num">155</td>
+                    <td class="coverage">333<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (dataset_1_one == dataset_2_two &amp;&amp; dataset_2_one == dataset_1_two) {</pre>
+                      <pre class="language-r">  structure(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">34</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">156</td>
+                    <td class="coverage">333<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (</pre>
+                      <pre class="language-r">    list(),</pre>
                     </td>
                   </tr>
-                  <tr class="missed">
-                    <td class="num">35</td>
-                    <td class="coverage">!</td>
+                  <tr class="covered">
+                    <td class="num">157</td>
+                    <td class="coverage">333<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      xor(length(keys_one) == 0, length(keys_two) == 0) ||</pre>
+                      <pre class="language-r">    class = c("join_keys", "list"),</pre>
                     </td>
                   </tr>
-                  <tr class="missed">
-                    <td class="num">36</td>
-                    <td class="coverage">!</td>
+                  <tr class="covered">
+                    <td class="num">158</td>
+                    <td class="coverage">333<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        !identical(sort(keys_one), sort(stats::setNames(names(keys_two), keys_two)))</pre>
+                      <pre class="language-r">    "parents" = list()</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">37</td>
+                    <td class="num">159</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    ) {</pre>
+                      <pre class="language-r">  )</pre>
                     </td>
                   </tr>
-                  <tr class="missed">
-                    <td class="num">38</td>
-                    <td class="coverage">!</td>
+                  <tr class="never">
+                    <td class="num">160</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      stop_message(dataset_1_one, dataset_2_one)</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
+                </tbody>
+              </table>
+            </div>
+            <div id="R/verify.R" class="hidden">
+              <table class="table-condensed">
+                <tbody>
                   <tr class="never">
-                    <td class="num">39</td>
+                    <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#' Verify code reproducibility</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">40</td>
+                    <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">41</td>
+                    <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' Checks whether code in `teal_data` object reproduces the stored objects.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">42</td>
+                    <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # otherwise they are compatible</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">43</td>
-                    <td class="coverage">2<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">5</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  return(TRUE)</pre>
+                      <pre class="language-r">#' If objects created by code in the `@code` slot of `x` are `all_equal` to the contents of the `@env` slot,</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">44</td>
+                    <td class="num">6</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#' the function updates the `@verified` slot to `TRUE` in the returned `teal_data` object.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">45</td>
+                    <td class="num">7</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' Once verified, the slot will always be set to `TRUE`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">46</td>
+                    <td class="num">8</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Validate parent-child key</pre>
+                      <pre class="language-r">#' If the `@code` fails to recreate objects in `teal_data@env`, an error is raised.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">47</td>
+                    <td class="num">9</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">48</td>
+                    <td class="num">10</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Helper function checks the parent-child relations are valid.</pre>
+                      <pre class="language-r">#' @return Input `teal_data` object or error.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">49</td>
+                    <td class="num">11</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">50</td>
+                    <td class="num">12</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param x (`join_keys`) object to assert validity of relations</pre>
+                      <pre class="language-r">#' @param x `teal_data` object</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">51</td>
+                    <td class="num">13</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">52</td>
+                    <td class="num">14</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return `join_keys` invisibly</pre>
+                      <pre class="language-r">#' tdata1 &lt;- teal_data()</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">53</td>
+                    <td class="num">15</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' tdata1 &lt;- within(tdata1, {</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">54</td>
+                    <td class="num">16</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">#'   a &lt;- 1</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">55</td>
+                    <td class="num">17</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">assert_parent_child &lt;- function(x) {</pre>
+                      <pre class="language-r">#'   b &lt;- a^5</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">56</td>
-                    <td class="coverage">441<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">18</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  jk &lt;- join_keys(x)</pre>
+                      <pre class="language-r">#'   c &lt;- list(x = 2)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">57</td>
-                    <td class="coverage">441<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">19</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  jk_parents &lt;- parents(jk)</pre>
+                      <pre class="language-r">#' })</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">58</td>
+                    <td class="num">20</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' verify(tdata1)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">59</td>
-                    <td class="coverage">441<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">21</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_class(jk, c("join_keys", "list"))</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">60</td>
+                    <td class="num">22</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' tdata2 &lt;- teal_data(x1 = iris, code = "x1 &lt;- iris")</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">61</td>
-                    <td class="coverage">441<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">23</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (!is.null(jk_parents)) {</pre>
+                      <pre class="language-r">#' verify(tdata2)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">62</td>
-                    <td class="coverage">441<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">24</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    for (idx1 in seq_along(jk_parents)) {</pre>
+                      <pre class="language-r">#' verify(tdata2)@verified</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">63</td>
-                    <td class="coverage">177<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">25</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      name_from &lt;- names(jk_parents)[[idx1]]</pre>
+                      <pre class="language-r">#' tdata2@verified</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">64</td>
-                    <td class="coverage">177<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">26</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      for (idx2 in seq_along(jk_parents[[idx1]])) {</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">65</td>
-                    <td class="coverage">177<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">27</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        name_to &lt;- jk_parents[[idx1]][[idx2]]</pre>
+                      <pre class="language-r">#' tdata3 &lt;- teal_data()</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">66</td>
-                    <td class="coverage">177<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">28</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        keys_from &lt;- jk[[name_from]][[name_to]]</pre>
+                      <pre class="language-r">#' tdata3 &lt;- within(tdata3, {</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">67</td>
-                    <td class="coverage">177<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">29</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        keys_to &lt;- jk[[name_to]][[name_from]]</pre>
+                      <pre class="language-r">#'   stop("error")</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">68</td>
-                    <td class="coverage">177<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">30</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        if (length(keys_from) == 0 &amp;&amp; length(keys_to) == 0) {</pre>
+                      <pre class="language-r">#' })</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">69</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">31</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#' try(verify(tdata3)) # fails</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">32</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          stop(sprintf("No join keys from %s to its parent (%s) and vice versa", name_from, name_to))</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">70</td>
+                    <td class="num">33</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        }</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">71</td>
+                    <td class="num">34</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r">#' a &lt;- 1</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">72</td>
+                    <td class="num">35</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#' b &lt;- a + 2</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">73</td>
+                    <td class="num">36</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' c &lt;- list(x = 2)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">74</td>
-                    <td class="coverage">440<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">37</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  invisible(x)</pre>
+                      <pre class="language-r">#' d &lt;- 5</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">75</td>
+                    <td class="num">38</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#' tdata4 &lt;- teal_data(</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">76</td>
+                    <td class="num">39</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#'   a = a, b = b, c = c, d = d,</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">77</td>
+                    <td class="num">40</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Verify key set compatibility</pre>
+                      <pre class="language-r">#'   code = "a &lt;- 1</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">78</td>
+                    <td class="num">41</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#'           b &lt;- a</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">79</td>
+                    <td class="num">42</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Helper function to ensuring compatibility between two sets of keys</pre>
+                      <pre class="language-r">#'           c &lt;- list(x = 2)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">80</td>
+                    <td class="num">43</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#'           e &lt;- 1"</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">81</td>
+                    <td class="num">44</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return Returns `TRUE` if successful, otherwise raises error.</pre>
+                      <pre class="language-r">#' )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">82</td>
+                    <td class="num">45</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">#' tdata4</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">83</td>
+                    <td class="num">46</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">assert_compatible_keys2 &lt;- function(x, y) {</pre>
+                      <pre class="language-r">#' \dontrun{</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">84</td>
+                    <td class="num">47</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # Helper to flatten join_keys / join_key_set</pre>
+                      <pre class="language-r">#' verify(tdata4) # fails</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">85</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">48</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  flatten_join_key_sets &lt;- function(value) {</pre>
+                      <pre class="language-r">#' }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">86</td>
-                    <td class="coverage">6<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">49</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    value &lt;- unclass(value)</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">87</td>
-                    <td class="coverage">6<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">50</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    Reduce(</pre>
+                      <pre class="language-r">#' @name verify</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">88</td>
-                    <td class="coverage">6<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">51</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      init = list(),</pre>
+                      <pre class="language-r">#' @rdname verify</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">89</td>
-                    <td class="coverage">6<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">52</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      f = function(u, v, ...) {</pre>
+                      <pre class="language-r">#' @aliases verify,teal_data-method</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">90</td>
-                    <td class="coverage">6<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">53</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        el &lt;- value[v][[1]]</pre>
+                      <pre class="language-r">#' @aliases verify,qenv.error-method</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">91</td>
-                    <td class="coverage">6<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">54</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        res &lt;- lapply(seq_along(el), function(ix) el[ix])</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">92</td>
-                    <td class="coverage">6<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">55</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        names(res) &lt;- rep(v, length(res))</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">93</td>
-                    <td class="coverage">6<em>x</em></td>
+                    <td class="num">56</td>
+                    <td class="coverage">5<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        append(u, res)</pre>
+                      <pre class="language-r">setGeneric("verify", function(x) standardGeneric("verify"))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">94</td>
+                    <td class="num">57</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      },</pre>
+                      <pre class="language-r">setMethod("verify", signature = "teal_data", definition = function(x) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">95</td>
-                    <td class="coverage">6<em>x</em></td>
+                    <td class="num">58</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      x = names(value)</pre>
+                      <pre class="language-r">  if (x@verified) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">96</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">59</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    )</pre>
+                      <pre class="language-r">    return(x)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">97</td>
+                    <td class="num">60</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">98</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
                   <tr class="covered">
-                    <td class="num">99</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="num">61</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x &lt;- flatten_join_key_sets(x)</pre>
+                      <pre class="language-r">  x_name &lt;- deparse(substitute(x))</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">100</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="num">62</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  y &lt;- flatten_join_key_sets(y)</pre>
+                      <pre class="language-r">  y &lt;- eval_code(teal_data(), get_code(x))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">101</td>
+                    <td class="num">63</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">102</td>
-                    <td class="coverage">3<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  for (idx_1 in seq_along(x)) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">103</td>
-                    <td class="coverage">3<em>x</em></td>
+                    <td class="num">64</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    for (idx_2 in seq_along(y)) {</pre>
+                      <pre class="language-r">  if (inherits(y, "qenv.error")) {</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">104</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="missed">
+                    <td class="num">65</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      assert_compatible_keys(x[idx_1], y[idx_2])</pre>
+                      <pre class="language-r">    stop(conditionMessage(y), call. = FALSE)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">105</td>
+                    <td class="num">66</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">106</td>
+                    <td class="num">67</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">107</td>
+                    <td class="num">68</td>
                     <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  TRUE</pre>
+                      <pre class="language-r">  reproduced &lt;- isTRUE(all.equal(x@env, y@env))</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">108</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">69</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">  if (reproduced) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">109</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">70</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">    x@verified &lt;- TRUE</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">110</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">71</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Updates the keys of the datasets based on the parents</pre>
+                      <pre class="language-r">    methods::validObject(x)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">111</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">72</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    x</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">112</td>
+                    <td class="num">73</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param x (`join_keys`) object to update the keys.</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">113</td>
-                    <td class="coverage"></td>
+                      <pre class="language-r">  } else {</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">74</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    error &lt;- "Code verification failed."</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">114</td>
+                    <td class="num">75</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return (`self`) invisibly for chaining</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">115</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">76</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    objects_diff &lt;- vapply(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">116</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">77</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">      intersect(names(x@env), names(y@env)),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">117</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">78</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">update_keys_given_parents &lt;- function(x) {</pre>
+                      <pre class="language-r">      function(element) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">118</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="num">79</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  jk &lt;- join_keys(x)</pre>
+                      <pre class="language-r">        isTRUE(all.equal(x@env[[element]], y@env[[element]]))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">119</td>
+                    <td class="num">80</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">      },</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">120</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="num">81</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_class(jk, "join_keys", .var.name = checkmate::vname(x))</pre>
+                      <pre class="language-r">      logical(1)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">121</td>
+                    <td class="num">82</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">    )</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">122</td>
-                    <td class="coverage">12<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">83</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  datanames &lt;- names(jk)</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">123</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="num">84</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  for (d1_ix in seq_along(datanames)) {</pre>
+                      <pre class="language-r">    names_diff_other &lt;- setdiff(names(y@env), names(x@env))</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">124</td>
-                    <td class="coverage">34<em>x</em></td>
+                    <td class="num">85</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    d1 &lt;- datanames[[d1_ix]]</pre>
+                      <pre class="language-r">    names_diff_inenv &lt;- setdiff(names(x@env), names(y@env))</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">125</td>
-                    <td class="coverage">34<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">86</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    d1_parent &lt;- parent(jk, d1)</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">126</td>
-                    <td class="coverage">34<em>x</em></td>
+                    <td class="num">87</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    for (d2 in datanames[-1 * seq.int(d1_ix)]) {</pre>
+                      <pre class="language-r">    if (length(objects_diff)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">127</td>
-                    <td class="coverage">38<em>x</em></td>
+                    <td class="num">88</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      if (length(jk[[d1]][[d2]]) == 0) {</pre>
+                      <pre class="language-r">      error &lt;- c(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">128</td>
-                    <td class="coverage">16<em>x</em></td>
+                    <td class="num">89</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        d2_parent &lt;- parent(jk, d2)</pre>
+                      <pre class="language-r">        error,</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">129</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">90</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">        paste0("Object(s) recreated with code that have different structure in ", x_name, ":"),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">130</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="num">91</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        if (!identical(d1_parent, d2_parent) || length(d1_parent) == 0) next</pre>
+                      <pre class="language-r">        paste0("  \u2022 ", names(which(!objects_diff)))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">131</td>
+                    <td class="num">92</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">      )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">132</td>
+                    <td class="num">93</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        # both has the same parent -&gt; common keys to parent</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">133</td>
-                    <td class="coverage">4<em>x</em></td>
+                    <td class="num">94</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        keys_d1_parent &lt;- sort(jk[[d1]][[d1_parent]])</pre>
+                      <pre class="language-r">    if (length(names_diff_inenv)) {</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">134</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="missed">
+                    <td class="num">95</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        keys_d2_parent &lt;- sort(jk[[d2]][[d2_parent]])</pre>
+                      <pre class="language-r">      error &lt;- c(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">135</td>
-                    <td class="coverage"></td>
+                  <tr class="missed">
+                    <td class="num">96</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">        error,</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">136</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="missed">
+                    <td class="num">97</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        common_ix_1 &lt;- unname(keys_d1_parent) %in% unname(keys_d2_parent)</pre>
+                      <pre class="language-r">        paste0("Object(s) not created with code that exist in ", x_name, ":"),</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">137</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="missed">
+                    <td class="num">98</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        common_ix_2 &lt;- unname(keys_d2_parent) %in% unname(keys_d1_parent)</pre>
+                      <pre class="language-r">        paste0("  \u2022 ", names_diff_inenv)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">138</td>
+                    <td class="num">99</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">      )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">139</td>
+                    <td class="num">100</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        # No common keys between datasets - leave empty</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">140</td>
+                    <td class="num">101</td>
                     <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        if (all(!common_ix_1)) next</pre>
+                      <pre class="language-r">    if (length(names_diff_other)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">141</td>
-                    <td class="coverage"></td>
+                  <tr class="missed">
+                    <td class="num">102</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">      error &lt;- c(</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">142</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="missed">
+                    <td class="num">103</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        fk &lt;- structure(</pre>
+                      <pre class="language-r">        error,</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">143</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="missed">
+                    <td class="num">104</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          names(keys_d2_parent)[common_ix_2],</pre>
+                      <pre class="language-r">        paste0("Object(s) created with code that do not exist in ", x_name, ":"),</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">144</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="missed">
+                    <td class="num">105</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          names = names(keys_d1_parent)[common_ix_1]</pre>
+                      <pre class="language-r">        paste0("  \u2022 ", names_diff_other)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">145</td>
+                    <td class="num">106</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        )</pre>
+                      <pre class="language-r">      )</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">146</td>
-                    <td class="coverage">3<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">107</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        jk[[d1]][[d2]] &lt;- fk # mutate join key</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">147</td>
+                    <td class="num">108</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">148</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">109</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">    stop(paste(error, collapse = "\n"), call. = FALSE)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">149</td>
+                    <td class="num">110</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">150</td>
+                    <td class="num">111</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # check parent child relation</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">151</td>
-                    <td class="coverage">12<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  assert_parent_child(x = jk)</pre>
+                      <pre class="language-r">})</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">152</td>
+                    <td class="num">112</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">setMethod("verify", signature = "qenv.error", definition = function(x) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">153</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="num">113</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  jk</pre>
+                      <pre class="language-r">  stop(conditionMessage(x), call. = FALSE)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">154</td>
+                    <td class="num">114</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">})</pre>
                     </td>
                   </tr>
                 </tbody>
               </table>
             </div>
-            <div id="R/join_keys.R" class="hidden">
+            <div id="R/join_keys-utils.R" class="hidden">
               <table class="table-condensed">
                 <tbody>
                   <tr class="never">
                     <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Manage relationships between datasets using `join_keys`</pre>
+                      <pre class="language-r">#' Check Compatibility of keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @order 1</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @name join_keys</pre>
+                      <pre class="language-r">#' Helper function to assert if two key sets contain incompatible keys.</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -14469,490 +11160,490 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">5</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @usage ## Constructor, getter and setter</pre>
+                      <pre class="language-r">#' @return Returns `TRUE` if successful, otherwise raises error.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">6</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' join_keys(...)</pre>
+                      <pre class="language-r">#' @keywords internal</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">7</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">assert_compatible_keys &lt;- function(join_key_1, join_key_2) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">8</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @description</pre>
+                      <pre class="language-r">  stop_message &lt;- function(dataset_1, dataset_2) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">9</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Facilitates the creation and retrieval of relationships between datasets.</pre>
+                      <pre class="language-r">    stop(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">10</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' `join_keys` class extends `list` and contains keys connecting pairs of datasets.</pre>
+                      <pre class="language-r">      paste("cannot specify multiple different join keys between datasets:", dataset_1, "and", dataset_2)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">11</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Each element of the list contains keys for specific dataset.</pre>
+                      <pre class="language-r">    )</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">12</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Each dataset can have a relationship with itself (primary key) and with other datasets.</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">13</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">14</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Note that `join_keys` list is symmetrical and assumes a default direction, that is:</pre>
+                      <pre class="language-r">  dataset_1_one &lt;- names(join_key_1)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">15</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' when keys are set between `ds1` and `ds2`, it defines `ds1` as the parent</pre>
+                      <pre class="language-r">  dataset_2_one &lt;- names(join_key_1[[1]])</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">16</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' in a parent-child relationship and the mapping is automatically mirrored between</pre>
+                      <pre class="language-r">  keys_one &lt;- join_key_1[[1]][[1]]</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">17</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' `ds2` and `ds1`.</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">18</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  dataset_1_two &lt;- names(join_key_2)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">19</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @section Methods (by class):</pre>
+                      <pre class="language-r">  dataset_2_two &lt;- names(join_key_2[[1]])</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">20</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - `join_keys()`: Returns an empty `join_keys` object when called without arguments.</pre>
+                      <pre class="language-r">  keys_two &lt;- join_key_2[[1]][[1]]</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">21</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - `join_keys(join_keys)`: Returns itself.</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">22</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - `join_keys(teal_data)`: Returns the `join_keys` object contained in `teal_data` object.</pre>
+                      <pre class="language-r">  # if first datasets and the second datasets match and keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">23</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - `join_keys(...)`: Creates a new object with one or more `join_key_set` parameters.</pre>
+                      <pre class="language-r">  # must contain the same named elements</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">24</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  if (dataset_1_one == dataset_1_two &amp;&amp; dataset_2_one == dataset_2_two) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">25</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param ... optional,</pre>
+                      <pre class="language-r">    if (!identical(sort(keys_one), sort(keys_two))) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">26</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - either `teal_data` or `join_keys` object to extract `join_keys`</pre>
+                      <pre class="language-r">      stop_message(dataset_1_one, dataset_2_one)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">27</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - or any number of `join_key_set` objects to create `join_keys`</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">28</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - or nothing to create an empty `join_keys`</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">29</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param value For `x[i, j, directed = TRUE)] &lt;- value` (named/unnamed `character`)</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">30</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Column mapping between datasets.</pre>
+                      <pre class="language-r">  # if first dataset of join_key_1 matches second dataset of join_key_2</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">31</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  # and the first dataset of join_key_2 must match second dataset of join_key_1</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">32</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' For `join_keys(x) &lt;- value`: (`join_key_set` or list of `join_key_set`) relationship</pre>
+                      <pre class="language-r">  # and keys must contain the same elements but with names and values swapped</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">33</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' pairs to add to `join_keys` list.</pre>
+                      <pre class="language-r">  if (dataset_1_one == dataset_2_two &amp;&amp; dataset_2_one == dataset_1_two) {</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">34</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    if (</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">35</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      xor(length(keys_one) == 0, length(keys_two) == 0) ||</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">36</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return `join_keys` object.</pre>
+                      <pre class="language-r">        !identical(sort(keys_one), sort(stats::setNames(names(keys_two), keys_two)))</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">37</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    ) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">38</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">      stop_message(dataset_1_one, dataset_2_one)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">39</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Creating a new join keys ----</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">40</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">41</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk &lt;- join_keys(</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">42</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   join_key("ds1", "ds1", "pk1"),</pre>
+                      <pre class="language-r">  # otherwise they are compatible</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">43</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   join_key("ds2", "ds2", "pk2"),</pre>
+                      <pre class="language-r">  return(TRUE)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">44</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   join_key("ds3", "ds3", "pk3"),</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">45</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   join_key("ds1", "ds2", c(pk1 = "pk2")),</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">46</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   join_key("ds1", "ds3", c(pk1 = "pk3"))</pre>
+                      <pre class="language-r">#' Validate parent-child key</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">47</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' )</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">48</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' Helper function checks the parent-child relations are valid.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">49</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">50</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @param x (`join_keys`) object to assert validity of relations</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">51</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">52</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @return `join_keys` invisibly</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">53</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @seealso [join_key()] for creating `join_keys_set`,</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">54</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' [parents()] for parent operations,</pre>
+                      <pre class="language-r">#' @keywords internal</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">55</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' [teal_data()] for `teal_data` constructor _and_</pre>
+                      <pre class="language-r">assert_parent_child &lt;- function(x) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">56</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">441<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' [default_cdisc_join_keys] for default CDISC keys.</pre>
+                      <pre class="language-r">  jk &lt;- join_keys(x)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">57</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">441<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  jk_parents &lt;- parents(jk)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">58</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">join_keys &lt;- function(...) {</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">59</td>
-                    <td class="coverage">820<em>x</em></td>
+                    <td class="coverage">441<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (missing(...)) {</pre>
+                      <pre class="language-r">  checkmate::assert_class(jk, c("join_keys", "list"))</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">60</td>
-                    <td class="coverage">245<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    return(new_join_keys())</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">61</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">441<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">  if (!is.null(jk_parents)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">62</td>
-                    <td class="coverage">575<em>x</em></td>
+                    <td class="coverage">441<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x &lt;- rlang::list2(...)</pre>
+                      <pre class="language-r">    for (idx1 in seq_along(jk_parents)) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">63</td>
-                    <td class="coverage">575<em>x</em></td>
+                    <td class="coverage">177<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (length(x) == 1L) {</pre>
+                      <pre class="language-r">      name_from &lt;- names(jk_parents)[[idx1]]</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">64</td>
-                    <td class="coverage">510<em>x</em></td>
+                    <td class="coverage">177<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    UseMethod("join_keys", x[[1]])</pre>
+                      <pre class="language-r">      for (idx2 in seq_along(jk_parents[[idx1]])) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">65</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">177<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else {</pre>
+                      <pre class="language-r">        name_to &lt;- jk_parents[[idx1]][[idx2]]</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">66</td>
-                    <td class="coverage">65<em>x</em></td>
+                    <td class="coverage">177<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    join_keys.default(...)</pre>
+                      <pre class="language-r">        keys_from &lt;- jk[[name_from]][[name_to]]</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">67</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">177<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">        keys_to &lt;- jk[[name_to]][[name_from]]</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">68</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">177<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">        if (length(keys_from) == 0 &amp;&amp; length(keys_to) == 0) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">69</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">          stop(sprintf("No join keys from %s to its parent (%s) and vice versa", name_from, name_to))</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">70</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname join_keys</pre>
+                      <pre class="language-r">        }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">71</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @order 1</pre>
+                      <pre class="language-r">      }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">72</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">73</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">join_keys.default &lt;- function(...) {</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">74</td>
-                    <td class="coverage">113<em>x</em></td>
+                    <td class="coverage">440<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  c(new_join_keys(), ...)</pre>
+                      <pre class="language-r">  invisible(x)</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -14973,217 +11664,217 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">77</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname join_keys</pre>
+                      <pre class="language-r">#' Verify key set compatibility</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">78</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @order 1</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">79</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">#' Helper function to ensuring compatibility between two sets of keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">80</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">join_keys.join_keys &lt;- function(...) {</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">81</td>
-                    <td class="coverage">457<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x &lt;- rlang::list2(...)</pre>
+                      <pre class="language-r">#' @return Returns `TRUE` if successful, otherwise raises error.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">82</td>
-                    <td class="coverage">457<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x[[1]]</pre>
+                      <pre class="language-r">#' @keywords internal</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">83</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">assert_compatible_keys2 &lt;- function(x, y) {</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">84</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">  # Helper to flatten join_keys / join_key_set</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">85</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname join_keys</pre>
+                      <pre class="language-r">  flatten_join_key_sets &lt;- function(value) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">86</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @order 1</pre>
+                      <pre class="language-r">    value &lt;- unclass(value)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">87</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">    Reduce(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">88</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">join_keys.teal_data &lt;- function(...) {</pre>
+                      <pre class="language-r">      init = list(),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">89</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x &lt;- rlang::list2(...)</pre>
+                      <pre class="language-r">      f = function(u, v, ...) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">90</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x[[1]]@join_keys</pre>
+                      <pre class="language-r">        el &lt;- value[v][[1]]</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">91</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">        res &lt;- lapply(seq_along(el), function(ix) el[ix])</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">92</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">        names(res) &lt;- rep(v, length(res))</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">93</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname join_keys</pre>
+                      <pre class="language-r">        append(u, res)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">94</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @order 5</pre>
+                      <pre class="language-r">      },</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">95</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">6<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      x = names(value)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">96</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @section Functions:</pre>
+                      <pre class="language-r">    )</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">97</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' - `join_keys(x) &lt;- value`: Assignment of the `join_keys` in object with `value`.</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">98</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' `value` needs to be an object of class `join_keys` or `join_key_set`.</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">99</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  x &lt;- flatten_join_key_sets(x)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">100</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param x (`join_keys`) empty object to set the new relationship pairs.</pre>
+                      <pre class="language-r">  y &lt;- flatten_join_key_sets(y)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">101</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' `x` is typically an object of `join_keys` class. When called with the `join_keys(x)`</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">102</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' or `join_keys(x) &lt;- value` then it can also take a supported class (`teal_data`, `join_keys`)</pre>
+                      <pre class="language-r">  for (idx_1 in seq_along(x)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">103</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    for (idx_2 in seq_along(y)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">104</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">      assert_compatible_keys(x[idx_1], y[idx_2])</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">105</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">`join_keys&lt;-` &lt;- function(x, value) {</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">106</td>
-                    <td class="coverage">16<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_class(value, classes = c("join_keys", "list"))</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">107</td>
-                    <td class="coverage">16<em>x</em></td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  UseMethod("join_keys&lt;-", x)</pre>
+                      <pre class="language-r">  TRUE</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -15204,1745 +11895,1856 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">110</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname join_keys</pre>
+                      <pre class="language-r">#' Updates the keys of the datasets based on the parents</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">111</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @order 5</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">112</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">#' @param x (`join_keys`) object to update the keys.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">113</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">114</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Assigning keys via join_keys(x)[i, j] &lt;- value ----</pre>
+                      <pre class="language-r">#' @return (`self`) invisibly for chaining</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">115</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#'</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">116</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#' @keywords internal</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">117</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">update_keys_given_parents &lt;- function(x) {</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">118</td>
+                    <td class="coverage">12<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  jk &lt;- join_keys(x)</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">119</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r"></pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">120</td>
+                    <td class="coverage">12<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  checkmate::assert_class(jk, "join_keys", .var.name = checkmate::vname(x))</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">121</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r"></pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">122</td>
+                    <td class="coverage">12<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  datanames &lt;- names(jk)</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">123</td>
+                    <td class="coverage">12<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  for (d1_ix in seq_along(datanames)) {</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">124</td>
+                    <td class="coverage">34<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">    d1 &lt;- datanames[[d1_ix]]</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">125</td>
+                    <td class="coverage">34<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">    d1_parent &lt;- parent(jk, d1)</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">126</td>
+                    <td class="coverage">34<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">    for (d2 in datanames[-1 * seq.int(d1_ix)]) {</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">127</td>
+                    <td class="coverage">38<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">      if (length(jk[[d1]][[d2]]) == 0) {</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">128</td>
+                    <td class="coverage">16<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">        d2_parent &lt;- parent(jk, d2)</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">129</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r"></pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">130</td>
+                    <td class="coverage">12<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">        if (!identical(d1_parent, d2_parent) || length(d1_parent) == 0) next</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">115</td>
+                    <td class="num">131</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">116</td>
+                    <td class="num">132</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' obj &lt;- join_keys()</pre>
+                      <pre class="language-r">        # both has the same parent -&gt; common keys to parent</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">117</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">133</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # or</pre>
+                      <pre class="language-r">        keys_d1_parent &lt;- sort(jk[[d1]][[d1_parent]])</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">118</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">134</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' obj &lt;- teal_data()</pre>
+                      <pre class="language-r">        keys_d2_parent &lt;- sort(jk[[d2]][[d2_parent]])</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">119</td>
+                    <td class="num">135</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">120</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">136</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' join_keys(obj)["ds1", "ds1"] &lt;- "pk1"</pre>
+                      <pre class="language-r">        common_ix_1 &lt;- unname(keys_d1_parent) %in% unname(keys_d2_parent)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">121</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">137</td>
+                    <td class="coverage">4<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' join_keys(obj)["ds2", "ds2"] &lt;- "pk2"</pre>
+                      <pre class="language-r">        common_ix_2 &lt;- unname(keys_d2_parent) %in% unname(keys_d1_parent)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">122</td>
+                    <td class="num">138</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' join_keys(obj)["ds3", "ds3"] &lt;- "pk3"</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">123</td>
+                    <td class="num">139</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' join_keys(obj)["ds1", "ds2"] &lt;- c(pk1 = "pk2")</pre>
+                      <pre class="language-r">        # No common keys between datasets - leave empty</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">124</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">140</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' join_keys(obj)["ds1", "ds3"] &lt;- c(pk1 = "pk3")</pre>
+                      <pre class="language-r">        if (all(!common_ix_1)) next</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">125</td>
+                    <td class="num">141</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">126</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">142</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' identical(jk, join_keys(obj))</pre>
+                      <pre class="language-r">        fk &lt;- structure(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">127</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">143</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">`join_keys&lt;-.join_keys` &lt;- function(x, value) {</pre>
+                      <pre class="language-r">          names(keys_d2_parent)[common_ix_2],</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">128</td>
-                    <td class="coverage">10<em>x</em></td>
+                    <td class="num">144</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  value</pre>
+                      <pre class="language-r">          names = names(keys_d1_parent)[common_ix_1]</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">129</td>
+                    <td class="num">145</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">        )</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">130</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">146</td>
+                    <td class="coverage">3<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">        jk[[d1]][[d2]] &lt;- fk # mutate join key</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">131</td>
+                    <td class="num">147</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname join_keys</pre>
+                      <pre class="language-r">      }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">132</td>
+                    <td class="num">148</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @order 5</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">133</td>
+                    <td class="num">149</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">134</td>
+                    <td class="num">150</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">  # check parent child relation</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">135</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">151</td>
+                    <td class="coverage">12<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Setter for join_keys within teal_data ----</pre>
+                      <pre class="language-r">  assert_parent_child(x = jk)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">136</td>
+                    <td class="num">152</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">137</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">153</td>
+                    <td class="coverage">12<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' td &lt;- teal_data()</pre>
+                      <pre class="language-r">  jk</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">138</td>
+                    <td class="num">154</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' join_keys(td) &lt;- jk</pre>
+                      <pre class="language-r">}</pre>
                     </td>
                   </tr>
+                </tbody>
+              </table>
+            </div>
+            <div id="R/teal_data-show.R" class="hidden">
+              <table class="table-condensed">
+                <tbody>
                   <tr class="never">
-                    <td class="num">139</td>
+                    <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' Show `teal_data` object</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">140</td>
+                    <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' join_keys(td)["ds1", "ds2"] &lt;- "new_key"</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">141</td>
+                    <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' join_keys(td) &lt;- c(join_keys(td), join_keys(join_key("ds3", "ds2", "key3")))</pre>
+                      <pre class="language-r">#' Prints `teal_data` object.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">142</td>
+                    <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' join_keys(td)</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">143</td>
+                    <td class="num">5</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">`join_keys&lt;-.teal_data` &lt;- function(x, value) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">144</td>
-                    <td class="coverage">6<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  join_keys(x@join_keys) &lt;- value</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">145</td>
-                    <td class="coverage">6<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  datanames(x) &lt;- x@datanames # datanames fun manages some exceptions</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">146</td>
-                    <td class="coverage">6<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  x</pre>
+                      <pre class="language-r">#' @param object (`teal_data`)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">147</td>
+                    <td class="num">6</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#' @return Input `teal_data` object.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">148</td>
+                    <td class="num">7</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @importFrom methods show</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">149</td>
+                    <td class="num">8</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Internal constructor</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">150</td>
+                    <td class="num">9</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' teal_data()</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">151</td>
+                    <td class="num">10</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return an empty `join_keys` list</pre>
+                      <pre class="language-r">#' teal_data(x = iris, code = "x = iris")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">152</td>
+                    <td class="num">11</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' verify(teal_data(x = iris, code = "x = iris"))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">153</td>
+                    <td class="num">12</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">154</td>
+                    <td class="num">13</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">new_join_keys &lt;- function() {</pre>
+                      <pre class="language-r">setMethod("show", signature = "teal_data", function(object) {</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">155</td>
-                    <td class="coverage">382<em>x</em></td>
+                  <tr class="missed">
+                    <td class="num">14</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  structure(</pre>
+                      <pre class="language-r">  if (object@verified) {</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">156</td>
-                    <td class="coverage">382<em>x</em></td>
+                  <tr class="missed">
+                    <td class="num">15</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    list(),</pre>
+                      <pre class="language-r">    cat("\u2705\ufe0e", "verified teal_data object\n")</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">157</td>
-                    <td class="coverage">382<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">16</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    class = c("join_keys", "list"),</pre>
+                      <pre class="language-r">  } else {</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">158</td>
-                    <td class="coverage">382<em>x</em></td>
+                  <tr class="missed">
+                    <td class="num">17</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    "parents" = list()</pre>
+                      <pre class="language-r">    cat("\u2716", "unverified teal_data object\n")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">159</td>
+                    <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
+                      <pre class="language-r">  }</pre>
+                    </td>
+                  </tr>
+                  <tr class="missed">
+                    <td class="num">19</td>
+                    <td class="coverage">!</td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  rlang::env_print(object@env)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">160</td>
+                    <td class="num">20</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">})</pre>
                     </td>
                   </tr>
                 </tbody>
               </table>
             </div>
-            <div id="R/join_keys-print.R" class="hidden">
+            <div id="R/teal_data-get_code.R" class="hidden">
               <table class="table-condensed">
                 <tbody>
                   <tr class="never">
                     <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname join_keys</pre>
+                      <pre class="language-r">#' Get code from `teal_data` object</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @order 7</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">#' Retrieve code from `teal_data` object.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">format.join_keys &lt;- function(x, ...) {</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">5</td>
-                    <td class="coverage">6<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (length(x) &gt; 0) {</pre>
+                      <pre class="language-r">#' Retrieve code stored in `@code`, which (in principle) can be used to recreate all objects found in `@env`.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">6</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    my_parents &lt;- parents(x)</pre>
+                      <pre class="language-r">#' Use `names` to limit the code to one or more of the datasets enumerated in `@datanames`.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">7</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    names_sorted &lt;- topological_sort(my_parents)</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">8</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    names &lt;- union(names_sorted, names(x))</pre>
+                      <pre class="language-r">#' @section Extracting dataset-specific code:</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">9</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    x_implicit &lt;- update_keys_given_parents(x)</pre>
+                      <pre class="language-r">#' When `names` is specified, the code returned will be limited  to the lines needed to _create_</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">10</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    out &lt;- lapply(names, function(i) {</pre>
+                      <pre class="language-r">#' the requested datasets. The code stored in the `@code` slot is analyzed statically to determine</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">11</td>
-                    <td class="coverage">15<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      out_i &lt;- lapply(union(i, names(x[[i]])), function(j) {</pre>
+                      <pre class="language-r">#' which lines the datasets of interest depend upon. The analysis works well when objects are created</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">12</td>
-                    <td class="coverage">35<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        direction &lt;- if (identical(my_parents[[j]], i)) {</pre>
+                      <pre class="language-r">#' with standard infix assignment operators (see `?assignOps`) but it can fail in some situations.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">13</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          "  &lt;-- "</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">14</td>
-                    <td class="coverage">35<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        } else if (identical(my_parents[[i]], j)) {</pre>
+                      <pre class="language-r">#' Consider the following examples:</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">15</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          "  --&gt; "</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">16</td>
-                    <td class="coverage">35<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        } else if (!identical(i, j)) {</pre>
+                      <pre class="language-r">#' _Case 1: Usual assignments._</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">17</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          "  &lt;-&gt; "</pre>
+                      <pre class="language-r">#' ```r</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        } else {</pre>
+                      <pre class="language-r">#' data &lt;- teal_data() |&gt;</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">19</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          ""</pre>
+                      <pre class="language-r">#'   within({</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">20</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        }</pre>
+                      <pre class="language-r">#'     foo &lt;- function(x) {</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">21</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#'       x + 1</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">22</td>
-                    <td class="coverage">35<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        keys &lt;- x[[i]][[j]]</pre>
+                      <pre class="language-r">#'     }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">23</td>
-                    <td class="coverage">35<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        sprintf(</pre>
+                      <pre class="language-r">#'     x &lt;- 0</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">24</td>
-                    <td class="coverage">35<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          "%s%s: [%s]",</pre>
+                      <pre class="language-r">#'     y &lt;- foo(x)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">25</td>
-                    <td class="coverage">35<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          direction, j,</pre>
+                      <pre class="language-r">#'   })</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">26</td>
-                    <td class="coverage">35<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          if (length(keys) == 0) "no primary keys" else toString(keys)</pre>
+                      <pre class="language-r">#' get_code(data, names = "y")</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">27</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        )</pre>
+                      <pre class="language-r">#' ```</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">28</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      })</pre>
+                      <pre class="language-r">#' `x` has no dependencies, so `get_code(data, names = "x")` will return only the second call.\cr</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">29</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' `y` depends on `x` and `foo`, so `get_code(data, names = "y")` will contain all three calls.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">30</td>
-                    <td class="coverage">15<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      implicit_datasets &lt;- setdiff(names(x_implicit[[i]]), names(x[[i]]))</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">31</td>
-                    <td class="coverage">15<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      if (length(implicit_datasets) &gt; 0) {</pre>
+                      <pre class="language-r">#' _Case 2: Some objects are created by a function's side effects._</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">32</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        out_i &lt;- c(</pre>
+                      <pre class="language-r">#' ```r</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">33</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          out_i,</pre>
+                      <pre class="language-r">#' data &lt;- teal_data() |&gt;</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">34</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          paste0(</pre>
+                      <pre class="language-r">#'   within({</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">35</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">            "  --* (implicit via parent with): ",</pre>
+                      <pre class="language-r">#'     foo &lt;- function() {</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">36</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">            paste(implicit_datasets, collapse = ", ")</pre>
+                      <pre class="language-r">#'       x &lt;&lt;- x + 1</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">37</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">          )</pre>
+                      <pre class="language-r">#'     }</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">38</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        )</pre>
+                      <pre class="language-r">#'     x &lt;- 0</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">39</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      }</pre>
+                      <pre class="language-r">#'     foo()</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">40</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#'     y &lt;- x</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">41</td>
-                    <td class="coverage">15<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      paste(out_i, collapse = "\n")</pre>
+                      <pre class="language-r">#'   })</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">42</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    })</pre>
+                      <pre class="language-r">#' get_code(data, names = "y")</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">43</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    paste(</pre>
+                      <pre class="language-r">#' ```</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">44</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      c(</pre>
+                      <pre class="language-r">#' Here, `y` depends on `x` but `x` is modified by `foo` as a side effect (not by reassignment)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">45</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        sprintf("A join_keys object containing foreign keys between %s datasets:", length(x)),</pre>
+                      <pre class="language-r">#' and so `get_code(data, names = "y")` will not return the `foo()` call.\cr</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">46</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">        out</pre>
+                      <pre class="language-r">#' To overcome this limitation, code dependencies can be specified manually.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">47</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      ),</pre>
+                      <pre class="language-r">#' Lines where side effects occur can be flagged by adding "`# @linksto &lt;object name&gt;`" at the end.\cr</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">48</td>
-                    <td class="coverage">5<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      collapse = "\n"</pre>
+                      <pre class="language-r">#' Note that `within` evaluates code passed to `expr` as is and comments are ignored.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">49</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    )</pre>
+                      <pre class="language-r">#' In order to include comments in code one must use the `eval_code` function instead.</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">50</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#'</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">51</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#' ```r</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">52</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#' data &lt;- teal_data() |&gt;</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">53</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#'   eval_code("</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">54</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#'     foo &lt;- function() {</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">55</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#'       x &lt;&lt;- x + 1</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">56</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">#'     }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">50</td>
+                    <td class="num">57</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  } else {</pre>
+                      <pre class="language-r">#'     x &lt;- 0</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">51</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">58</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    "An empty join_keys object."</pre>
+                      <pre class="language-r">#'     foo() # @linksto x</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">52</td>
+                    <td class="num">59</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#'     y &lt;- x</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">53</td>
+                    <td class="num">60</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#'   ")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">54</td>
+                    <td class="num">61</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' get_code(data, names = "y")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">55</td>
+                    <td class="num">62</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname join_keys</pre>
+                      <pre class="language-r">#' ```</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">56</td>
+                    <td class="num">63</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @order 7</pre>
+                      <pre class="language-r">#' Now the `foo()` call will be properly included in the code required to recreate `y`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">57</td>
+                    <td class="num">64</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">58</td>
+                    <td class="num">65</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">print.join_keys &lt;- function(x, ...) {</pre>
+                      <pre class="language-r">#' Note that two functions that create objects as side effects, `assign` and `data`, are handled automatically.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">59</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">66</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  cat(format(x, ...), "\n")</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">60</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">67</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  invisible(x)</pre>
+                      <pre class="language-r">#' Here are known cases where manual tagging is necessary:</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">61</td>
+                    <td class="num">68</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#' - non-standard assignment operators, _e.g._ `%&lt;&gt;%`</pre>
                     </td>
                   </tr>
-                </tbody>
-              </table>
-            </div>
-            <div id="R/join_keys-parents.R" class="hidden">
-              <table class="table-condensed">
-                <tbody>
                   <tr class="never">
-                    <td class="num">1</td>
+                    <td class="num">69</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Get and set parents in `join_keys` object</pre>
+                      <pre class="language-r">#' - objects used as conditions in `if` statements: `if (&lt;condition&gt;)`</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">2</td>
+                    <td class="num">70</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' - objects used to iterate over in `for` loops: `for(i in &lt;sequence&gt;)`</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">3</td>
+                    <td class="num">71</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' `parents()` facilitates the creation of dependencies between datasets by</pre>
+                      <pre class="language-r">#' - creating and evaluating language objects, _e.g._ `eval(&lt;call&gt;)`</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">4</td>
+                    <td class="num">72</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' assigning a parent-child relationship.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">5</td>
+                    <td class="num">73</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">6</td>
+                    <td class="num">74</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Each element is defined by a `list` element, where `list("child" = "parent")`.</pre>
+                      <pre class="language-r">#' @param object (`teal_data`)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">7</td>
+                    <td class="num">75</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @param datanames `r lifecycle::badge("deprecated")` (`character`) vector of dataset names to return the code for.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">8</td>
+                    <td class="num">76</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param x (`join_keys` or `teal_data`) object that contains "parents" information</pre>
+                      <pre class="language-r">#' For more details see the "Extracting dataset-specific code" section. Use `names` instead.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">9</td>
+                    <td class="num">77</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' to retrieve or manipulate.</pre>
+                      <pre class="language-r">#' @param names (`character`) Successor of `datanames`. Vector of dataset names to return the code for.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">10</td>
+                    <td class="num">78</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' For more details see the "Extracting dataset-specific code" section.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">11</td>
+                    <td class="num">79</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return a `list` of `character` representing the parents.</pre>
+                      <pre class="language-r">#' @param deparse (`logical`) flag specifying whether to return code as `character` (`deparse = TRUE`) or as</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">12</td>
+                    <td class="num">80</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' `expression` (`deparse = FALSE`).</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">13</td>
+                    <td class="num">81</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">#' @param ... Parameters passed to internal methods. Currently, the only supported parameter is `check_names`</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">14</td>
+                    <td class="num">82</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @seealso [join_keys()]</pre>
+                      <pre class="language-r">#' (`logical(1)`) flag,  which is `TRUE` by default. Function warns about missing objects, if they do not exist in</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">15</td>
+                    <td class="num">83</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">parents &lt;- function(x) {</pre>
+                      <pre class="language-r">#' `code` but are passed in `datanames`. To remove the warning, set `check_names = FALSE`.</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">16</td>
-                    <td class="coverage">702<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">84</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  UseMethod("parents", x)</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">17</td>
+                    <td class="num">85</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#' @return</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">18</td>
+                    <td class="num">86</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' Either a character string or an expression. If `names` is used to request a specific dataset,</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">19</td>
+                    <td class="num">87</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @describeIn parents Retrieves parents of `join_keys` object.</pre>
+                      <pre class="language-r">#' only code that _creates_ that dataset (not code that uses it) is returned. Otherwise, all contents of `@code`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">20</td>
+                    <td class="num">88</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">21</td>
+                    <td class="num">89</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">22</td>
+                    <td class="num">90</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Get parents of join_keys ---</pre>
+                      <pre class="language-r">#' tdata1 &lt;- teal_data()</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">23</td>
+                    <td class="num">91</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' tdata1 &lt;- within(tdata1, {</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">24</td>
+                    <td class="num">92</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk &lt;- default_cdisc_join_keys["ADEX"]</pre>
+                      <pre class="language-r">#'   a &lt;- 1</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">25</td>
+                    <td class="num">93</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' parents(jk)</pre>
+                      <pre class="language-r">#'   b &lt;- a^5</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">26</td>
+                    <td class="num">94</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">parents.join_keys &lt;- function(x) {</pre>
+                      <pre class="language-r">#'   c &lt;- list(x = 2)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">27</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">95</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (is.null(attr(x, "parents"))) list() else attr(x, "parents")</pre>
+                      <pre class="language-r">#' })</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">28</td>
+                    <td class="num">96</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">#' get_code(tdata1)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">29</td>
+                    <td class="num">97</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' get_code(tdata1, names = "a")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">30</td>
+                    <td class="num">98</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @describeIn parents Retrieves parents of `join_keys` inside `teal_data` object.</pre>
+                      <pre class="language-r">#' get_code(tdata1, names = "b")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">31</td>
+                    <td class="num">99</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">32</td>
+                    <td class="num">100</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">#' tdata2 &lt;- teal_data(x1 = iris, code = "x1 &lt;- iris")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">33</td>
+                    <td class="num">101</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Get parents of join_keys inside teal_data object ---</pre>
+                      <pre class="language-r">#' get_code(tdata2)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">34</td>
+                    <td class="num">102</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' get_code(verify(tdata2))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">35</td>
+                    <td class="num">103</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' td &lt;- teal_data(</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">36</td>
+                    <td class="num">104</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   ADSL = rADSL,</pre>
+                      <pre class="language-r">#' @rdname get_code</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">37</td>
+                    <td class="num">105</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   ADTTE = rADTTE,</pre>
+                      <pre class="language-r">#' @aliases get_code,teal_data-method</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">38</td>
+                    <td class="num">106</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   ADRS = rADRS,</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">39</td>
+                    <td class="num">107</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   join_keys = default_cdisc_join_keys[c("ADSL", "ADTTE", "ADRS")]</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">40</td>
+                    <td class="num">108</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' )</pre>
+                      <pre class="language-r">setMethod("get_code",</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">41</td>
+                    <td class="num">109</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' parents(td)</pre>
+                      <pre class="language-r">  signature = "teal_data",</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">42</td>
+                    <td class="num">110</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">parents.teal_data &lt;- function(x) {</pre>
+                      <pre class="language-r">  definition = function(object, deparse = TRUE, names = NULL, datanames = lifecycle::deprecated(), ...) {</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">111</td>
+                    <td class="coverage">2<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">    if (lifecycle::is_present(datanames)) {</pre>
+                    </td>
+                  </tr>
+                  <tr class="missed">
+                    <td class="num">112</td>
+                    <td class="coverage">!</td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">      lifecycle::deprecate_warn(</pre>
+                    </td>
+                  </tr>
+                  <tr class="missed">
+                    <td class="num">113</td>
+                    <td class="coverage">!</td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">        when = "0.6.1",</pre>
+                    </td>
+                  </tr>
+                  <tr class="missed">
+                    <td class="num">114</td>
+                    <td class="coverage">!</td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">        what = "teal.data::get_code(datanames)",</pre>
+                    </td>
+                  </tr>
+                  <tr class="missed">
+                    <td class="num">115</td>
+                    <td class="coverage">!</td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">        with = "teal.code::get_code(names)",</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">43</td>
-                    <td class="coverage">1<em>x</em></td>
+                  <tr class="missed">
+                    <td class="num">116</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  parents(x@join_keys)</pre>
+                      <pre class="language-r">        always = TRUE</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">44</td>
+                    <td class="num">117</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">      )</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">45</td>
-                    <td class="coverage"></td>
+                  <tr class="missed">
+                    <td class="num">118</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">      names &lt;- datanames</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">46</td>
+                    <td class="num">119</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @describeIn parents Assignment of parents in `join_keys` object.</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">47</td>
+                    <td class="num">120</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">48</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">121</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param value (`named list`) of `character` vectors.</pre>
+                      <pre class="language-r">    if (!is.null(names) &amp;&amp; lifecycle::is_present(datanames)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">49</td>
-                    <td class="coverage"></td>
+                  <tr class="missed">
+                    <td class="num">122</td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">      stop("Please use either 'names' (recommended) or 'datanames' parameter.")</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">50</td>
+                    <td class="num">123</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">51</td>
+                    <td class="num">124</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">`parents&lt;-` &lt;- function(x, value) {</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">52</td>
-                    <td class="coverage">438<em>x</em></td>
+                    <td class="num">125</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  UseMethod("parents&lt;-", x)</pre>
+                      <pre class="language-r">    checkmate::assert_character(names, min.len = 1L, null.ok = TRUE)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">53</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">126</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">    checkmate::assert_flag(deparse)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">54</td>
+                    <td class="num">127</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">55</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">128</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @describeIn parents Assignment of parents of `join_keys` object.</pre>
+                      <pre class="language-r">    methods::callNextMethod(object = object, deparse = deparse, names = names, ...)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">56</td>
+                    <td class="num">129</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">57</td>
+                    <td class="num">130</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">)</pre>
                     </td>
                   </tr>
+                </tbody>
+              </table>
+            </div>
+            <div id="R/teal_data-datanames.R" class="hidden">
+              <table class="table-condensed">
+                <tbody>
                   <tr class="never">
-                    <td class="num">58</td>
+                    <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Assignment of parents ---</pre>
+                      <pre class="language-r">#' Names of data sets in `teal_data` object</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">59</td>
+                    <td class="num">2</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">60</td>
+                    <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' jk &lt;- join_keys(</pre>
+                      <pre class="language-r">#' Get or set the value of the `datanames` slot.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">61</td>
+                    <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   join_key("ds1", "ds2", "id"),</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">62</td>
+                    <td class="num">5</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   join_key("ds5", "ds6", "id"),</pre>
+                      <pre class="language-r">#' The `@datanames` slot in a `teal_data` object specifies which of the variables stored in its environment</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">63</td>
+                    <td class="num">6</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'   join_key("ds7", "ds6", "id")</pre>
+                      <pre class="language-r">#' (the `@env` slot) are data sets to be taken into consideration.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">64</td>
+                    <td class="num">7</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' )</pre>
+                      <pre class="language-r">#' The contents of `@datanames` can be specified upon creation and default to all variables in `@env`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">65</td>
+                    <td class="num">8</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' Variables created later, which may well be data sets, are not automatically considered such.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">66</td>
+                    <td class="num">9</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' parents(jk) &lt;- list(ds2 = "ds1")</pre>
+                      <pre class="language-r">#' Use this function to update the slot.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">67</td>
+                    <td class="num">10</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">68</td>
-                    <td class="coverage"></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">#' # Setting individual parent-child relationship</pre>
-                    </td>
-                  </tr>
-                  <tr class="never">
-                    <td class="num">69</td>
+                    <td class="num">11</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @param x (`teal_data`) object to access or modify</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">70</td>
+                    <td class="num">12</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' parents(jk)["ds6"] &lt;- "ds5"</pre>
+                      <pre class="language-r">#' @param value (`character`) new value for `@datanames`; all elements must be names of variables existing in `@env`</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">71</td>
+                    <td class="num">13</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' parents(jk)["ds7"] &lt;- "ds6"</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">72</td>
+                    <td class="num">14</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">`parents&lt;-.join_keys` &lt;- function(x, value) {</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">73</td>
-                    <td class="coverage">437<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_list(value, types = "character", names = "named")</pre>
+                      <pre class="language-r">#' @return The contents of `@datanames` or `teal_data` object with updated `@datanames`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">74</td>
+                    <td class="num">15</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">75</td>
-                    <td class="coverage">434<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  new_parents &lt;- list()</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">76</td>
+                    <td class="num">16</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">77</td>
-                    <td class="coverage">434<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  for (dataset in names(value)) {</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">78</td>
+                    <td class="num">17</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    # Custom .var.name so it is verbose and helpful for users</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">79</td>
-                    <td class="coverage">168<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    checkmate::assert_string(value[[dataset]], .var.name = sprintf("value[[\"%s\"]]", dataset))</pre>
+                      <pre class="language-r">#' td &lt;- teal_data(iris = iris)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">80</td>
+                    <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">81</td>
-                    <td class="coverage">167<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    parent &lt;- new_parents[[dataset]]</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">82</td>
-                    <td class="coverage">167<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">    checkmate::assert(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">83</td>
-                    <td class="coverage">167<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      checkmate::check_null(parent),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">84</td>
-                    <td class="coverage">167<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      checkmate::check_true(</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">85</td>
-                    <td class="coverage">167<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">        length(parent) == 0 &amp;&amp;</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">86</td>
-                    <td class="coverage">167<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">          length(value[[dataset]]) == 0</pre>
+                      <pre class="language-r">#' td &lt;- within(td, mtcars &lt;- mtcars)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">87</td>
+                    <td class="num">19</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      ),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">88</td>
-                    <td class="coverage">167<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      checkmate::check_true(parent == value[[dataset]]),</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">89</td>
-                    <td class="coverage">167<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      "Please check the difference between provided datasets parents and provided join_keys parents.",</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">90</td>
-                    <td class="coverage">167<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">      .var.name = "value"</pre>
+                      <pre class="language-r">#' datanames(td)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">91</td>
+                    <td class="num">20</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    )</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">92</td>
-                    <td class="coverage">167<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">21</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    if (is.null(parent)) {</pre>
+                      <pre class="language-r">#' datanames(td) &lt;- c("iris", "mtcars")</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">93</td>
-                    <td class="coverage">167<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">22</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">      new_parents[[dataset]] &lt;- value[[dataset]]</pre>
+                      <pre class="language-r">#' datanames(td)</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">94</td>
+                    <td class="num">23</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    }</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">95</td>
+                    <td class="num">24</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' @name datanames</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">96</td>
+                    <td class="num">25</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @aliases datanames,teal_data-method</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">97</td>
-                    <td class="coverage">433<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">26</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  if (is_dag(new_parents)) {</pre>
+                      <pre class="language-r">#' @aliases datanames&lt;-,teal_data,character-method</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">98</td>
-                    <td class="coverage">4<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">27</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    stop("Cycle detected in a parent and child dataset graph.")</pre>
+                      <pre class="language-r">#' @aliases datanames,qenv.error-method</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">99</td>
+                    <td class="num">28</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  }</pre>
+                      <pre class="language-r">#' @aliases datanames&lt;-,qenv.error,character-method</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">100</td>
+                    <td class="num">29</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
-                    <td class="num">101</td>
-                    <td class="coverage">429<em>x</em></td>
+                  <tr class="never">
+                    <td class="num">30</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  attr(x, "parents") &lt;- new_parents</pre>
+                      <pre class="language-r">#' @rdname datanames</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">102</td>
+                    <td class="num">31</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">103</td>
-                    <td class="coverage">429<em>x</em></td>
+                    <td class="num">32</td>
+                    <td class="coverage">15<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  assert_parent_child(x)</pre>
+                      <pre class="language-r">setGeneric("datanames", function(x) standardGeneric("datanames"))</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">33</td>
+                    <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">setMethod("datanames", signature = "teal_data", definition = function(x) {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">104</td>
-                    <td class="coverage">428<em>x</em></td>
+                    <td class="num">34</td>
+                    <td class="coverage">13<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x</pre>
+                      <pre class="language-r">  x@datanames</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">105</td>
+                    <td class="num">35</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">})</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">106</td>
+                    <td class="num">36</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">setMethod("datanames", signature = "qenv.error", definition = function(x) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">107</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">37</td>
+                    <td class="coverage">2<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @describeIn parents Assignment of parents of `join_keys` inside `teal_data` object.</pre>
+                      <pre class="language-r">  NULL</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">108</td>
+                    <td class="num">38</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">})</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">109</td>
+                    <td class="num">39</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">110</td>
+                    <td class="num">40</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Assignment of parents of join_keys inside teal_data object ---</pre>
+                      <pre class="language-r">#' @rdname datanames</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">111</td>
+                    <td class="num">41</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">112</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">42</td>
+                    <td class="coverage">14<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' parents(td) &lt;- list("ADTTE" = "ADSL") # replace existing</pre>
+                      <pre class="language-r">setGeneric("datanames&lt;-", function(x, value) standardGeneric("datanames&lt;-"))</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">113</td>
+                    <td class="num">43</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' parents(td)["ADRS"] &lt;- "ADSL" # add new parent</pre>
+                      <pre class="language-r">setMethod("datanames&lt;-", signature = c("teal_data", "character"), definition = function(x, value) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">114</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">44</td>
+                    <td class="coverage">13<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">`parents&lt;-.teal_data` &lt;- function(x, value) {</pre>
+                      <pre class="language-r">  checkmate::assert_subset(value, names(x@env))</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">115</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="num">45</td>
+                    <td class="coverage">12<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  parents(x@join_keys) &lt;- value</pre>
+                      <pre class="language-r">  x@datanames &lt;- .get_sorted_datanames(datanames = value, join_keys = x@join_keys, env = x@env)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">116</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="num">46</td>
+                    <td class="coverage">12<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  methods::validObject(x)</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">47</td>
+                    <td class="coverage">12<em>x</em></td>
                     <td class="col-sm-12">
                       <pre class="language-r">  x</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">117</td>
+                    <td class="num">48</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">}</pre>
+                      <pre class="language-r">})</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">118</td>
+                    <td class="num">49</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">setMethod("datanames&lt;-", signature = c("qenv.error", "character"), definition = function(x, value) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">119</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">50</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @describeIn parents Getter for individual parent.</pre>
+                      <pre class="language-r">  methods::validObject(x)</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">120</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">51</td>
+                    <td class="coverage">1<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  x</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">121</td>
+                    <td class="num">52</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param dataset_name (`character(1)`) Name of dataset to query on their parent.</pre>
+                      <pre class="language-r">})</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">122</td>
+                    <td class="num">53</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">123</td>
+                    <td class="num">54</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return For `parent(x, dataset_name)` returns `NULL` if parent does not exist.</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">124</td>
+                    <td class="num">55</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @keywords internal</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">125</td>
+                    <td class="num">56</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">.get_sorted_datanames &lt;- function(datanames, join_keys, env) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">126</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">57</td>
+                    <td class="coverage">60<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">  child_parent &lt;- sapply(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">127</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">58</td>
+                    <td class="coverage">60<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">    datanames,</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">128</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">59</td>
+                    <td class="coverage">60<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' # Get individual parent ---</pre>
+                      <pre class="language-r">    function(name) parent(join_keys, name),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">129</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">60</td>
+                    <td class="coverage">60<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">    USE.NAMES = TRUE,</pre>
                     </td>
                   </tr>
-                  <tr class="never">
-                    <td class="num">130</td>
-                    <td class="coverage"></td>
+                  <tr class="covered">
+                    <td class="num">61</td>
+                    <td class="coverage">60<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' parent(jk, "ds2")</pre>
+                      <pre class="language-r">    simplify = FALSE</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">131</td>
+                    <td class="num">62</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' parent(td, "ADTTE")</pre>
+                      <pre class="language-r">  )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">132</td>
+                    <td class="num">63</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">parent &lt;- function(x, dataset_name) {</pre>
+                      <pre class="language-r"></pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">64</td>
+                    <td class="coverage">60<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  union(</pre>
+                    </td>
+                  </tr>
+                  <tr class="covered">
+                    <td class="num">65</td>
+                    <td class="coverage">60<em>x</em></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">    intersect(unlist(topological_sort(child_parent)), ls(env)),</pre>
                     </td>
                   </tr>
                   <tr class="covered">
-                    <td class="num">133</td>
-                    <td class="coverage">179<em>x</em></td>
+                    <td class="num">66</td>
+                    <td class="coverage">60<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_string(dataset_name)</pre>
+                      <pre class="language-r">    datanames</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">134</td>
+                    <td class="num">67</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  # assert x is performed by parents()</pre>
-                    </td>
-                  </tr>
-                  <tr class="covered">
-                    <td class="num">135</td>
-                    <td class="coverage">179<em>x</em></td>
-                    <td class="col-sm-12">
-                      <pre class="language-r">  parents(x)[[dataset_name]]</pre>
+                      <pre class="language-r">  )</pre>
                     </td>
                   </tr>
                   <tr class="never">
-                    <td class="num">136</td>
+                    <td class="num">68</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">}</pre>
@@ -17251,14 +14053,14 @@ <h2>teal.data coverage - 89.08%</h2>
                 </tbody>
               </table>
             </div>
-            <div id="R/teal_data-datanames.R" class="hidden">
+            <div id="R/teal_data.R" class="hidden">
               <table class="table-condensed">
                 <tbody>
                   <tr class="never">
                     <td class="num">1</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Names of data sets in `teal_data` object</pre>
+                      <pre class="language-r">#' Comprehensive data integration function for `teal` applications</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -17272,70 +14074,70 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">3</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Get or set the value of the `datanames` slot.</pre>
+                      <pre class="language-r">#' @description</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">4</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' `r lifecycle::badge("stable")`</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">5</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' The `@datanames` slot in a `teal_data` object specifies which of the variables stored in its environment</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">6</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' (the `@env` slot) are data sets to be taken into consideration.</pre>
+                      <pre class="language-r">#' Universal function to pass data to teal application.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">7</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' The contents of `@datanames` can be specified upon creation and default to all variables in `@env`.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">8</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Variables created later, which may well be data sets, are not automatically considered such.</pre>
+                      <pre class="language-r">#' @param ... any number of objects (presumably data objects) provided as `name = value` pairs.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">9</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' Use this function to update the slot.</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">10</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @param join_keys (`join_keys` or single `join_key_set`)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">11</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param x (`teal_data`) object to access or modify</pre>
+                      <pre class="language-r">#' optional object with datasets column names used for joining.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">12</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @param value (`character`) new value for `@datanames`; all elements must be names of variables existing in `@env`</pre>
+                      <pre class="language-r">#' If empty then no joins between pairs of objects.</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -17349,63 +14151,63 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">14</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @return The contents of `@datanames` or `teal_data` object with updated `@datanames`.</pre>
+                      <pre class="language-r">#' @param code (`character`, `language`) optional code to reproduce the datasets provided in `...`.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">15</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#'  Note this code is not executed and the `teal_data` may not be reproducible</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">16</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @examples</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">17</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' td &lt;- teal_data(iris = iris)</pre>
+                      <pre class="language-r">#' @param check (`logical`) `r lifecycle::badge("deprecated")`</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">18</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' td &lt;- within(td, mtcars &lt;- mtcars)</pre>
+                      <pre class="language-r">#'  Use [verify()] to verify code reproducibility .</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">19</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' datanames(td)</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">20</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#'</pre>
+                      <pre class="language-r">#' @return A `teal_data` object.</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">21</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' datanames(td) &lt;- c("iris", "mtcars")</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">22</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' datanames(td)</pre>
+                      <pre class="language-r">#' @export</pre>
                     </td>
                   </tr>
                   <tr class="never">
@@ -17419,313 +14221,320 @@ <h2>teal.data coverage - 89.08%</h2>
                     <td class="num">24</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @name datanames</pre>
+                      <pre class="language-r">#' @examples</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">25</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @aliases datanames,teal_data-method</pre>
+                      <pre class="language-r">#' teal_data(x1 = iris, x2 = mtcars)</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">26</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @aliases datanames&lt;-,teal_data,character-method</pre>
+                      <pre class="language-r">#'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">27</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @aliases datanames,qenv.error-method</pre>
+                      <pre class="language-r">teal_data &lt;- function(...,</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">28</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @aliases datanames&lt;-,qenv.error,character-method</pre>
+                      <pre class="language-r">                      join_keys = teal.data::join_keys(),</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">29</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">                      code = character(0),</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">30</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname datanames</pre>
+                      <pre class="language-r">                      check) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">31</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">  data_objects &lt;- rlang::list2(...)</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">32</td>
-                    <td class="coverage">15<em>x</em></td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">setGeneric("datanames", function(x) standardGeneric("datanames"))</pre>
+                      <pre class="language-r">  if (inherits(join_keys, "join_key_set")) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">33</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">setMethod("datanames", signature = "teal_data", definition = function(x) {</pre>
+                      <pre class="language-r">    join_keys &lt;- teal.data::join_keys(join_keys)</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">34</td>
-                    <td class="coverage">13<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x@datanames</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">35</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">})</pre>
+                      <pre class="language-r">  if (!missing(check)) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">36</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">setMethod("datanames", signature = "qenv.error", definition = function(x) {</pre>
+                      <pre class="language-r">    lifecycle::deprecate_stop(</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="missed">
                     <td class="num">37</td>
-                    <td class="coverage">2<em>x</em></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  NULL</pre>
+                      <pre class="language-r">      when = "0.4.0",</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">38</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">})</pre>
+                      <pre class="language-r">      "teal_data(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">39</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">        check = 'check argument is deprecated. Use `verify()` to verify code reproducibility.</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">40</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @rdname datanames</pre>
+                      <pre class="language-r">        Find more information on https://github.com/insightsengineering/teal/discussions/945'</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">41</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @export</pre>
+                      <pre class="language-r">      )"</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">42</td>
-                    <td class="coverage">14<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">setGeneric("datanames&lt;-", function(x, value) standardGeneric("datanames&lt;-"))</pre>
+                      <pre class="language-r">    )</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">43</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">setMethod("datanames&lt;-", signature = c("teal_data", "character"), definition = function(x, value) {</pre>
+                      <pre class="language-r">  }</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">44</td>
-                    <td class="coverage">13<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  checkmate::assert_subset(value, names(x@env))</pre>
+                      <pre class="language-r"></pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">45</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x@datanames &lt;- .get_sorted_datanames(datanames = value, join_keys = x@join_keys, env = x@env)</pre>
+                      <pre class="language-r">  if (</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">46</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  methods::validObject(x)</pre>
+                      <pre class="language-r">    checkmate::test_list(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">47</td>
-                    <td class="coverage">12<em>x</em></td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x</pre>
+                      <pre class="language-r">      data_objects,</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">48</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">})</pre>
+                      <pre class="language-r">      types = c("TealDataConnector", "TealDataset", "TealDatasetConnector"),</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">49</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">setMethod("datanames&lt;-", signature = c("qenv.error", "character"), definition = function(x, value) {</pre>
+                      <pre class="language-r">      min.len = 1</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">50</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  methods::validObject(x)</pre>
+                      <pre class="language-r">    )</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">51</td>
-                    <td class="coverage">1<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  x</pre>
+                      <pre class="language-r">  ) {</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">52</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">})</pre>
+                      <pre class="language-r">    lifecycle::deprecate_stop(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">53</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">      when = "0.4.0",</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">54</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">      "teal_data(</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">55</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">#' @keywords internal</pre>
+                      <pre class="language-r">        data_objects = 'should use data directly. Using TealDatasetConnector and TealDataset is deprecated.</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="missed">
                     <td class="num">56</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">.get_sorted_datanames &lt;- function(datanames, join_keys, env) {</pre>
+                      <pre class="language-r">        Find more information on https://github.com/insightsengineering/teal/discussions/945'</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">57</td>
-                    <td class="coverage">109<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  child_parent &lt;- sapply(</pre>
+                      <pre class="language-r">      )"</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">58</td>
-                    <td class="coverage">109<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    datanames,</pre>
+                      <pre class="language-r">    )</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="never">
                     <td class="num">59</td>
-                    <td class="coverage">109<em>x</em></td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    function(name) parent(join_keys, name),</pre>
+                      <pre class="language-r">  } else {</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">60</td>
-                    <td class="coverage">109<em>x</em></td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    USE.NAMES = TRUE,</pre>
+                      <pre class="language-r">    if (length(data_objects) &gt; 0 &amp;&amp; !checkmate::test_names(names(data_objects), type = "named")) {</pre>
                     </td>
                   </tr>
-                  <tr class="covered">
+                  <tr class="missed">
                     <td class="num">61</td>
-                    <td class="coverage">109<em>x</em></td>
+                    <td class="coverage">!</td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    simplify = FALSE</pre>
+                      <pre class="language-r">      stop("Dot (`...`) arguments on `teal_data()` must be named.")</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">62</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
+                      <pre class="language-r">    }</pre>
                     </td>
                   </tr>
-                  <tr class="never">
+                  <tr class="covered">
                     <td class="num">63</td>
-                    <td class="coverage"></td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r"></pre>
+                      <pre class="language-r">    new_teal_data(</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">64</td>
-                    <td class="coverage">109<em>x</em></td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  union(</pre>
+                      <pre class="language-r">      data = data_objects,</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">65</td>
-                    <td class="coverage">109<em>x</em></td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    intersect(unlist(topological_sort(child_parent)), ls(env)),</pre>
+                      <pre class="language-r">      code = code,</pre>
                     </td>
                   </tr>
                   <tr class="covered">
                     <td class="num">66</td>
-                    <td class="coverage">109<em>x</em></td>
+                    <td class="coverage">48<em>x</em></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">    datanames</pre>
+                      <pre class="language-r">      join_keys = join_keys</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">67</td>
                     <td class="coverage"></td>
                     <td class="col-sm-12">
-                      <pre class="language-r">  )</pre>
+                      <pre class="language-r">    )</pre>
                     </td>
                   </tr>
                   <tr class="never">
                     <td class="num">68</td>
                     <td class="coverage"></td>
+                    <td class="col-sm-12">
+                      <pre class="language-r">  }</pre>
+                    </td>
+                  </tr>
+                  <tr class="never">
+                    <td class="num">69</td>
+                    <td class="coverage"></td>
                     <td class="col-sm-12">
                       <pre class="language-r">}</pre>
                     </td>