add S4 generic for get_code for teal_data

R/teal_data-get_code.R

@@ -0,0 +1,51 @@
+#' Get Code from `teal_data`
+#'
+#' Get code from [`teal_data`]. The extraction of the code limited to specific objects can be performed with the usage
+#' of `names` parameter. If input `teal_data@verified` is `FALSE` the returned code is pre-pended with a warning
+#' stating that the object was not verified.
+#'
+#' @param x [`teal_data`] object.
+#' @param names (`character`) vector of object names to return the code for.
+#' @param deparse (`logical`) whether return deparsed form of a call.
+#' @return (`character`) code of import and preparation of data for `teal` application.
+#' @examples
+#'
+#' tdata1 <- teal_data()
+#' tdata1 <- within(tdata1, {
+#'   a <- 1
+#'   b <- a^5
+#'   c <- list(x = 2)
+#' })
+#' get_code(tdata1)
+#' datanames(tdata1) <- c("a", "b", "c")
+#' get_code(tdata1, "a")
+#' get_code(tdata1, "b")
+#'
+#' tdata2 <- teal_data(x1 = iris, code = "x1 = iris")
+#' get_code(tdata2)
+#' get_code(verify(tdata2))
+#' @aliases get_code,teal_data-method
+#' @export
+setGeneric("get_code", function(x, ...) standardGeneric("get_code"))
+setMethod("get_code", "teal_data", definition = function(x, names = NULL, deparse = TRUE) {
+
+  checkmate::assert_character(names, min.len = 1L, null.ok = TRUE)
+  checkmate::assert_subset(names, x@datanames, empty.ok = TRUE)
+  checkmate::assert_flag(deparse)
+
+  code <- if (!is.null(names)) {
+    get_code_dependency(x@code, names)
+  } else {
+    x@code
+  }
+
+  if (!x@verified) {
+    code <- c("warning('Code was not verified for reproducibility.')", code)
+  }
+
+  if (deparse) {
+    code
+  } else {
+    parse(text = code, keep.source = TRUE)
+  }
+})