Merge pull request #20 from kitlawes/master

Support nested lists in the toc

lib/table_of_contents/parser.rb

@@ -13,13 +13,75 @@ def initialize(html)
       def build_toc
         toc = %Q{<ul class="section-nav">\n}
 
+        min_h_num = 6
         @entries.each do |entry|
-          toc << %Q{<li class="toc-entry toc-#{entry[:node_name]}"><a href="##{entry[:id]}#{entry[:uniq]}">#{entry[:text]}</a></li>\n}
+          h_num = entry[:node_name].delete("h").to_i
+          min_h_num = [min_h_num, h_num].min
         end
+        toc << build_lis(@entries, min_h_num)
 
         toc << '</ul>'
       end
 
+      # Returns the list items for entries
+      def build_lis(entries, min_h_num)
+        lis = ""
+        i = 0
+        while i < entries.length do
+          entry = entries[i]
+          curr_h_num = entry[:node_name].delete("h").to_i
+          if curr_h_num == min_h_num
+
+            # If the current entry should not be indented in the list, add the entry to the list
+            lis << %Q{<li class="toc-entry toc-#{entry[:node_name]}"><a href="##{entry[:id]}#{entry[:uniq]}">#{entry[:text]}</a>}
+            # If the next entry should be indented in the list, generate a sublist
+            if i + 1 < entries.length
+              next_entry = entries[i + 1]
+              next_h_num = next_entry[:node_name].delete("h").to_i
+              if next_h_num > min_h_num
+                lis << %Q{\n}
+                lis << %Q{<ul>\n}
+                nest_entries = get_nest_entries(entries[i + 1, entries.length], min_h_num)
+                lis << build_lis(nest_entries, min_h_num + 1)
+                lis << %Q{</ul>\n}
+                i += nest_entries.length
+              end
+            end
+            # Add the closing tag for the current entry in the list
+            lis << %Q{</li>\n}
+
+          elsif curr_h_num > min_h_num
+
+            # If the current entry should be indented in the list, generate a sublist
+            lis << %Q{<ul>\n}
+            nest_entries = get_nest_entries(entries[i, entries.length], min_h_num)
+            lis << build_lis(nest_entries, min_h_num + 1)
+            lis << %Q{</ul>\n}
+            i += nest_entries.length - 1
+
+          end
+          i += 1
+        end
+        lis
+      end
+
+      # Returns the entries in a nested list
+      # The nested list starts at the first entry in entries (inclusive)
+      # The nested list ends at the first entry in entries with depth min_h_num or greater (exclusive)
+      def get_nest_entries(entries, min_h_num)
+        nest_entries = []
+        for i in 0..(entries.length - 1)
+          nest_entry = entries[i]
+          nest_h_num = nest_entry[:node_name].delete("h").to_i
+          if nest_h_num > min_h_num
+            nest_entries.push(nest_entry)
+          else
+            break
+          end
+        end
+        nest_entries
+      end
+
       def inject_anchors_into_html
         @entries.each do |entry|
           entry[:content_node].add_previous_sibling(%Q{<a id="#{entry[:id]}#{entry[:uniq]}" class="anchor" href="##{entry[:id]}#{entry[:uniq]}" aria-hidden="true"><span class="octicon octicon-link"></span></a>})