Adding \preformatted code block rendering (#16)

* adding preformatted block handling

Author: dgkf

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: rd2markdown
 Title: Convert Rd Files into Markdown
-Version: 0.0.2
+Version: 0.0.2.9000
 Authors@R: c(
     person(
         given = "Doug",
@@ -34,4 +34,4 @@ License: MIT + file LICENSE
 VignetteBuilder: knitr
 Encoding: UTF-8
 Roxygen: list(markdown = TRUE)
-RoxygenNote: 7.1.2
+RoxygenNote: 7.2.1

NAMESPACE

@@ -29,6 +29,7 @@ S3method(rd2markdown,list)
 S3method(rd2markdown,name)
 S3method(rd2markdown,note)
 S3method(rd2markdown,pkg)
+S3method(rd2markdown,preformatted)
 S3method(rd2markdown,references)
 S3method(rd2markdown,section)
 S3method(rd2markdown,seealso)

NEWS.md

@@ -1,9 +1,11 @@
 rd2markdown 0.0.2
 -----------------
 
-* minor change to S3 method exports (#1 @dgkf)
+* Adding preformatted code block handling (#15 @dgkf)
 
-* minor bug fix to header formatting (additional preceeding newline), which
+* Minor change to S3 method exports (#1 @dgkf)
+
+* Minor bug fix to header formatting (additional preceeding newline), which
   affects a subset of markdown renderers (#3 @dgkf)
 
 * Add `macros` parameter to `get_rd()` function to allow handling of 

R/_rd_sampler.R

@@ -24,6 +24,10 @@
 #' |----|---------|-------|
 #' | rd | sampler | table |
 #'
+#' ```
+#' preformatted code
+#' ```
+#'
 #' \eqn{Rd + sampler + inline + equation}
 #'
 #' \deqn{Rd * sampler * block * equation}
@@ -58,4 +62,8 @@
 #' @rdname rd_sampler
 #' @name rd_sampler
 #'
-NULL
+#' @importFrom utils help
+#' @keywords internal
+rd_sampler <- function(x, fragments, ...) {
+  utils::help("rd_sampler", package = packageName())
+}

R/rd2markdown.R

@@ -190,15 +190,22 @@ rd2markdown.examples <- function(x, fragments = c(), ...) {
   rd2markdown.usage(x, fragments = fragments, ..., title = "Examples")
 }
 
+#' @exportS3Method
+#' @rdname rd2markdown
+rd2markdown.usage <- function(...) {
+  rd2markdown.preformatted(..., language = "r")
+}
+
 #' @param title optional section title
+#' @param language language to use as code fence syntax highlighter
 #'
 #' @exportS3Method
 #' @rdname rd2markdown
-rd2markdown.usage <- function(x, fragments = c(), ..., title = NULL) {
+rd2markdown.preformatted <- function(x, fragments = c(), ..., title = NULL, language = "") {
   code <- capture.output(tools::Rd2txt(list(x), fragment = TRUE))
   code <- tail(code, -1L)  # remove "usage" title
   code <- gsub("^\\n?\\s{5}", "", code)  # remove leading white space
-  code <- sprintf("\n```r\n%s\n```\n\n", trimws(paste0(code, collapse = "\n")))
+  code <- sprintf("\n```%s\n%s\n```\n\n", language, trimws(paste0(code, collapse = "\n")))
   if (!is.null(title)) code <- sprintf("## %s\n%s", title, code)
   code
 }

man/rd2markdown.Rd

@@ -77,6 +77,16 @@ test_that("Rd document examples are properly rendered to markdown", {
 })
 
 test_that("Rd document details are properly rendered to markdown", {
+  rd <- get_rd(file = file.path(test_path(), "data", "man", "rd_sampler.Rd"))
+  details_frag <- rd[sapply(rd, function(i) attr(i, "Rd_tag") == "\\details")][[1]]
+  pre_frag <- details_frag[sapply(details_frag, function(i) attr(i, "Rd_tag") == "\\preformatted")][[1]]
+  expect_silent(md <- rd2markdown(pre_frag))
+  expect_match(trimws(md), trimws(pre_frag[[1L]]), fixed = TRUE)
+  expect_match(md, "^\\s*```")
+  expect_match(md, "```\\s*$")
+})
+
+test_that("Rd document preformatted code blocks are properly rendered to markdown", {
   rd <- get_rd(file = file.path(test_path(), "data", "man", "rd_sampler.Rd"))
   detail_frag <- rd[sapply(rd, function(i) attr(i, "Rd_tag") == "\\details")]
   expect_silent(md <- rd2markdown(detail_frag))