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Convert Quarto document to R script

Source: R/utils-extract.R
qmd_to_r_script.Rd

[Experimental]

Extracts R code cells from a Quarto document and writes them to an R script file that can be rendered with the same options. The Markdown text is not preserved, but R chunk options are kept as comment headers using Quarto's #| syntax.

This function is still experimental and may slightly change in future releases, depending on feedback.

Usage

qmd_to_r_script(qmd, script = NULL)

Arguments

qmd

Character. Path to the input Quarto document (.qmd file).

script

Character. Path to the output R script file. If NULL (default), the script file will have the same name as the input file but with .R extension.

Value

Invisibly returns the path to the created R script file, or NULL if no R code cells were found.

Details

This function processes a Quarto document by:

  • Extracting only R code cells (markdown and cell in other languages are ignored)

  • Preserving chunk options as #| comment headers

  • Adding the document's YAML metadata as a spin-style header

  • Creating an R script that can be rendered with the same options

Chunk option handling:

  • Chunks with purl: false are completely skipped and not included in the output

  • Chunks with eval: false have their code commented out (prefixed with # ) in the R script

  • All other chunk options are preserved as #| comment headers

File handling:

  • If the output R script already exists, the function will abort with an error

  • Non-R code cells (e.g., Python, Julia, Observable JS) are ignored

  • If no R code cells are found, the function does nothing and returns NULL

Compatibility:

The resulting R script is compatible with Quarto's script rendering via knitr::spin() and can be rendered directly with quarto render script.R. See https://quarto.org/docs/computations/render-scripts.html#knitr for more details on rendering R scripts with Quarto.

The resulting R script uses Quarto's executable cell format with #| comments to preserve chunk options like label, echo, output, etc.

The resulting R script could also be source()d in R, as any eval = FALSE will be commented out.

Limitations:

This function relies on static analysis of the Quarto document by quarto inspect. This means that any knitr specific options like child= or specific feature like knitr::read_chunk() are not supported. They rely on tangling or knitting by knitr itself. For this support, one should look at knitr::hook_purl() or knitr::purl().

Examples

if (FALSE) { # \dontrun{
# Convert a Quarto document to R script
qmd_to_r_script("my-document.qmd")
# Creates "my-document.R"

# Specify custom output file
qmd_to_r_script("my-document.qmd", script = "extracted-code.R")
} # }