Add functions to copy resources of Pandoc.

NAMESPACE

@@ -3,6 +3,8 @@
 S3method(knit_print,grouped_df)
 S3method(knit_print,rowwise_df)
 S3method(knit_print,tbl_sql)
+S3method(pandoc_copy_template,character)
+S3method(pandoc_copy_template,rmarkdown_output_format)
 S3method(prepare_evaluate_output,default)
 S3method(prepare_evaluate_output,htmlwidget)
 S3method(prepare_evaluate_output,knit_asis)
@@ -57,6 +59,8 @@ export(paged_table)
 export(pandoc_available)
 export(pandoc_citeproc_convert)
 export(pandoc_convert)
+export(pandoc_copy_data)
+export(pandoc_copy_template)
 export(pandoc_exec)
 export(pandoc_highlight_args)
 export(pandoc_include_args)

NEWS.md

@@ -5,6 +5,11 @@ rmarkdown 2.1
 
 - Ensure the `tempdir()` exists (via `tempdir(TRUE)`) when writing HTML dependencies to a temporary file, because this directory might be erased by accident (thanks, Kurt Hornik).
 
+- Add `pandoc_copy_data` to copy data files provided by Pandoc
+  (e.g, `pandoc_copy_data("reference.docx")`) (thanks, @atusy #1738)
+
+- Add `pandoc_copy_template` to copy templates provided by R Markdown or Pandoc.
+  (e.g., `pandoc_copy_template(html_document()`) (thanks, @atusy #1738)
 
 rmarkdown 2.0
 ================================================================================

R/pandoc_copy.R

@@ -0,0 +1,90 @@
+#' Copy a Pandoc's data file
+#'
+#' @param data The name of Pandoc's data file (e.g., "reference.docx")
+#' @param output The name of the output file. If \code{NULL} (default), the name
+#' will be same as the \code{data} argument.
+#' @param overwrite Whether or not to overwrite the existing file. Default to
+#' \code{FALSE}.
+#'
+#' @return The name of the output file.
+#'
+#' @seealso \url{https://pandoc.org/MANUAL.html#option--print-default-data-file}
+#'
+#' @examples
+#' \dontrun{
+#' pandoc_copy_data("reference.docx")
+#' }
+#'
+#' @export
+pandoc_copy_data <- function(data, output = data, overwrite = FALSE) {
+  if (file.exists(output) && !overwrite) {
+    message(output, " already exists.")
+    return(output)
+  }
+
+  system(paste(
+    quoted(pandoc()), "-o", output, "--print-default-data-file", data,
+    collapse = " "
+  ))
+  output
+}
+
+#' Copy a template file for Pandoc
+#'
+#' @param format To copy R Markdown's template, specify a result of a formatting
+#' function (e.g., \code{html_document()}). To copy Pandoc's original template,
+#' specify the format as a character (e.g., "html").
+#' @param output The name of the output file. If using \code{NULL} then the
+#' output filename will be based on the \code{format} argument.
+#' @inheritParams pandoc_copy_data
+#'
+#' @return The name of the output file.
+#'
+#' @seealso \url{https://pandoc.org/MANUAL.html#templates}
+#'
+#' @examples
+#' \dontrun{
+#' # Copy the html_document's template
+#' pandoc_copy_template(html_document())
+#'
+#' # Copy the Pandoc's html template
+#' pandoc_copy_template("html")
+#' }
+#'
+#' @export
+pandoc_copy_template <- function(format, output = NULL, overwrite = FALSE) {
+  UseMethod("pandoc_copy_template")
+}
+
+#' @export
+pandoc_copy_template.character <- function(
+  format, output = NULL, overwrite = FALSE
+) {
+  if (is.null(output)) output <- paste0("template.", format)
+  if (file.exists(output) && !overwrite) {
+    message(output, " already exists.")
+    return(output)
+  }
+
+  system(paste(
+    quoted(pandoc()), "-o", output, "--print-default-template", format,
+    collapse = " "
+  ))
+  output
+}
+
+#' @export
+pandoc_copy_template.rmarkdown_output_format <- function(
+  format, output = NULL, overwrite = FALSE
+) {
+  template <- format$pandoc$args[which(format$pandoc$args == "--template") + 1L]
+  if (is.null(output)) output <- sub(".*[\\/]", "", template)
+
+  if (file.exists(output) && !overwrite) {
+    message(output, " already exists.")
+    return(output)
+  }
+
+  file.copy(template, output, overwrite = overwrite)
+  output
+}