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roxygen2md

The goal of roxygen2md is to replace Rd syntax with Markdown in your package’s roxygen2 documentation. The following Rd code is converted to the Markdown equivalent:

  • \emph{}
  • \bold{} and \strong{}
  • \href{}
  • \url{}
  • \code{...}
  • Various variants of \code{\link{...}} and \code{\link[...]{...}} (only with scope = "full", see below)

If necessary, DESCRIPTION is edited to enable Markdown in roxygen blocks. You’ll need roxygen2 version 6.0.0 or later.

Call roxygen2md::roxygen2md() in your package’s directory, or navigate to “Tools/Addins/Rd to Markdown” in RStudio.

The substitutions are not completely safe, please carefully examine the results!

Installation

Install from CRAN using

install.packages("roxygen2md")

Get the latest development version from GitHub with:

# install.packages("pak", repos = sprintf("https://r-lib.github.io/p/pak/stable/%s/%s/%s", .Platform$pkgType, R.Version()$os, R.Version()$arch))
pak::pak("r-lib/roxygen2md")

Usage

In your package directory, run

roxygen2md::roxygen2md()

If you are using RStudio, choose the item “Rd to Markdown” from your “Addins” menu.

You will be guided through the process.

At any time, choose the item “Find Rd” from your “Addins” menu, or run find_rd(), to enumerate Rd elements in your R scripts.

Converting large packages

For larger existing packages, a three-stage workflow is recommended, using roxygen2md(scope = "none"), "simple" and "full" in sequence:

  • "none" only adds list(markdown = TRUE) to the Roxygen field in DESCRIPTION
  • "simple" only converts elements like \code{} and \emph{}
  • "full" runs all conversions
  • "unlink" splits complicated \code{} tags with embedded \link{}

This helps isolating mostly automated changes from changes that require review. After this find_rd() shows remaining Rd format artifacts that were not handled by the conversion.

See https://github.com/rstudio/rmarkdown/pull/1583 for an example conversion.

Baseline

After roxygen2md(scope = "none"), interpretation of Markdown elements is enabled. Running devtools::document() should ideally lead to whitespace-only changes in the .Rd files, this can be verified with git diff -w -- man or with a visual diff tool like Meld or diffuse. Make sure that enabling of Markdown doesn’t add unwanted artifacts. (The second commit in the example PR was necessary due to such artifacts – the underscore has a special meaning in Markdown.)

Simple conversion

Running roxygen2md(scope = "simple") after "none" (and running devtools::document()) should lead to changes in R files mostly, only very few .Rd files should be changed. Again, make sure this doesn’t add unwanted artifacts.

Optionally, run roxygen2md(scope = "unlink") after "simple" (and running devtools::document()). This replaces all instances of \link{...} with .... This isn’t a valid conversion, but a helper to split up complex instances of \code{...\link{...}...} for which no easy-to-read translation to Markdown exists. Use a visual diff tool like Meld or diffuse to quickly iterate through all changes and keep only those that are intended. Run devtools::document() and commit if necessary.

Consider inserting @seealso tags to link to functions instead. Render the documentation with pkgdown to take advantage of its auto-link feature – all functions gain automatic links without the need for further markup.

Full conversion

Running roxygen2md() after scope = "simple" (and running devtools::document()) converts all \link{} expressions. This is the trickiest part of the entire conversion. Due to the staged approach, the changeset is reduced to a minimum. Review carefully, luckily R CMD check catches bad links introduced in this stage.

Manual conversion

The find_rd() functions shows positions of Rd-like comments that were not handled by the conversion. In RStudio, a markers pane will open.

Limitations

The package’s DESCRIPTION must have its Encoding field set to UTF-8 or ASCII:

Encoding: UTF-8

If you use a different encoding, please recode your files with recode or a similar tool and update the Encoding field before proceeding. Example:

recode latin1..utf8 R/*

GPL-3 © Kirill Müller

Code of Conduct

Please note that the roxygen2md project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.