Spin goat's hair into wool

This function takes a specially formatted R script and converts it to a literate programming document. By default normal text (documentation) should be written after the roxygen comment (#') and code chunk options are written after #| or #+ or # %% or # ----.

Usage

spin(
  hair,
  knit = TRUE,
  report = TRUE,
  text = NULL,
  envir = parent.frame(),
  format = c("Rmd", "Rnw", "Rhtml", "Rtex", "Rrst", "qmd"),
  doc = "^#+'[ ]?",
  inline = "^[{][{](.+)[}][}][ ]*$",
  comment = c("^[# ]*/[*]", "^.*[*]/ *$"),
  precious = !knit && is.null(text)
)

Arguments

hair: Path to the R script. The script must be encoded in UTF-8 if it contains multibyte characters.
knit: Logical; whether to compile the document after conversion.
report: Logical; whether to generate a report for Rmd, Rnw and Rtex output. Ignored if knit = FALSE.
text: A character vector of code, as an alternative way to provide the R source. If text is not NULL, hair will be ignored.
envir: Environment for knit() to evaluate the code.
format: Character; the output format. The default is R Markdown.
doc: A regular expression to identify the documentation lines; by default it follows the roxygen convention, but it can be customized, e.g. if you want to use ## to denote documentation, you can use '^##\\s*'.
inline: A regular expression to identify inline R expressions; by default, code of the form {{code}} on its own line is treated as an inline expression.
comment: A pair of regular expressions for the start and end delimiters of comments; the lines between a start and an end delimiter will be ignored. By default, the delimiters are /* at the beginning of a line, and */ at the end, following the convention of C comments.
precious: logical: whether intermediate files (e.g., .Rmd files when format is "Rmd") should be preserved. The default is FALSE if knit is TRUE and the input is a file.

Value

If text is NULL, the path of the final output document, otherwise the content of the output.

Details

Obviously the goat's hair is the original R script, and the wool is the literate programming document (ready to be knitted).

Note

If the output format is Rnw and no document class is specified in roxygen comments, this function will automatically add the article class to the LaTeX document so that it is complete and can be compiled. You can always specify the document class and other LaTeX settings in roxygen comments manually.

When the output format is Rmd, it is compiled to HTML via knit2html(), which uses R Markdown v1 instead of v2. If you want to use the latter, you should call rmarkdown::render() instead. Similarly, if the output format is qmd, you need to render the output with Quarto.

References

https://yihui.org/knitr/demo/stitch/

Author

Yihui Xie, with the original idea from Richard FitzJohn (who named it as sowsear() which meant to make a silk purse out of a sow's ear)