Un-render a reprex

Recover clean, runnable code from a reprex captured in the wild and write it to user's clipboard. The code is also returned invisibly and optionally written to file. Three different functions address various forms of wild-caught reprex:

• reprex_invert() attempts to reverse the effect of reprex(). When venue = "r", this just calls reprex_clean().

• reprex_clean() removes commented output. This assumes that R code is top-level, possibly interleaved with commented output, e.g., a displayed reprex copied from GitHub or the output of reprex(..., venue = "R").

• reprex_rescue() removes lines of output and strips prompts from lines holding R commands. This assumes that R code lines start with a prompt and that printed output is top-level, e.g., what you'd if you've copied from the R Console.

reprex_invert(
  input = NULL,
  wd = NULL,
  venue = c("gh", "r"),
  comment = opt("#>"),
  outfile = deprecated()
)

reprex_clean(
  input = NULL,
  wd = NULL,
  comment = opt("#>"),
  outfile = deprecated()
)

reprex_rescue(
  input = NULL,
  wd = NULL,
  prompt = getOption("prompt"),
  continue = getOption("continue"),
  outfile = deprecated()
)

Arguments

input

Character. If has length one and lacks a terminating newline, interpreted as the path to a file containing the reprex. Otherwise, assumed to hold the reprex as a character vector. If not provided, the clipboard is consulted for input. If the clipboard is unavailable and we're in RStudio, the current selection is used.

wd

An optional filepath that is consulted when input is not a filepath. (By default, all work is done, quietly, in a subdirectory of the session temp directory.)

The most common use of wd is to set wd = ".", which means "reprex right HERE in the current working directory". Do this if you really must demonstrate something with local files.

venue

Character. Must be one of the following (case insensitive):

• "gh" for GitHub-Flavored Markdown, the default

• "r" for a runnable R script, with commented output interleaved. Also useful for Slack code snippets; select "R" from the "Type" drop-down menu to enjoy nice syntax highlighting.

• "rtf" for Rich Text Format (not supported for un-reprexing)

• "html" for an HTML fragment suitable for inclusion in a larger HTML document (not supported for un-reprexing)

• "slack" for pasting into a Slack message. Optimized for people who opt out of Slack's WYSIWYG interface. Go to Preferences > Advanced > Input options and select "Format messages with markup". (If there is demand for a second Slack venue optimized for use with WYSIWYG, please open an issue to discuss.)

• "so" for Stack Overflow Markdown. Note: this is just an alias for "gh", since Stack Overflow started to support CommonMark-style fenced code blocks in January 2019.

• "ds" for Discourse, e.g., forum.posit.co. Note: this is currently just an alias for "gh".

comment

regular expression that matches commented output lines

outfile

in favor of wd or providing a filepath to input. To reprex in current working directory, use wd = "." now, instead of outfile = NA.

prompt

character, the prompt at the start of R commands

continue

character, the prompt for continuation lines

Value

Character vector holding just the clean R code, invisibly

Examples

if (FALSE) { # \dontrun{
# a roundtrip: R code --> rendered reprex, as gfm --> R code
original <- file.path(tempdir(), "original.R")
writeLines(glue::glue("
  #' Some text
  #+ chunk-label-and-options-cannot-be-recovered, message = TRUE
  (x <- 1:4)
  #' More text
  y <- 2:5
  x + y"), con = original)
reprex(input = original, html_preview = FALSE, advertise = FALSE)
reprexed <- sub("[.]R$", "_reprex.md", original)
writeLines(readLines(reprexed))
unreprexed <- reprex_invert(input = reprexed)
writeLines(unreprexed)

# clean up
file.remove(
  list.files(dirname(original), pattern = "original", full.names = TRUE)
)
} # }
if (FALSE) { # \dontrun{
# a roundtrip: R code --> rendered reprex, as R code --> original R code
code_in <- c(
  "# a regular comment, which is retained",
  "(x <- 1:4)",
  "median(x)"
)
reprexed <- reprex(input = code_in, venue = "r", advertise = FALSE)
writeLines(reprexed)
code_out <- reprex_clean(input = reprexed)
writeLines(code_out)
identical(code_in, code_out)
} # }
if (FALSE) { # \dontrun{
# rescue a reprex that was copied from a live R session
from_r_console <- c(
  "> # a regular comment, which is retained",
  "> (x <- 1:4)",
  "[1] 1 2 3 4",
  "> median(x)",
  "[1] 2.5"
)
rescued <- reprex_rescue(input = from_r_console)
writeLines(rescued)
} # }