Inline vs. Chunk Execution of R Code: How to check from within a function?

[r-cheologist]

Description

Output of an R function that is to be used in both inline and chunk code execution needs (in the context of output: asis as a chunk execution option) to use cat() only in the latter case.

It would thus be convenient to be able to achieve what the following pdeudo-code demonstrates:

myfun <- function(x)
{
  if (IS_EXECUTED_INLINE) return(x) else cat(x)
}

Is there functionality available that provides access to the IS_EXECUTED_INLINE bit of information?

[mcanouil]

This is not up to Quarto (or rmarkdown for that matter).
You have to handle this yourself I am afraid.
You could register a new print method, knitr hooks, etc. to do what you want, see the "RMarkdown definitive guide" book for these.

• https://bookdown.org/yihui/rmarkdown/.

[r-cheologist]

Thank you, @mcanouil for sending me down the right path.

Exploring the output of knitr::knit_hooks$get("inline") & knitr::knit_hooks$get("chunk") led me to adding the following to my function, which should bring the output of any chunk in line with that of inline code:

knitr::knit_hooks$set(
    chunk  = function(x, options) {
      x %<>% stringi::stri_replace_first_regex(
        "^\\[\\d+\\]\\s*\"(.*)\"\\s*$", "$1")
      paste(as.character(x), collapse = ", ")
    })
on.exit(knitr::knit_hooks$restore())

This appears to do what I want.

[gadenbuie]

@r-cheologist Have you tried using knitr::asis_output(x)? With knitr, this is typically the best way to consistently return text that should be added literally into the document without having to resort to using cat().

[r-cheologist]

Interesting hint and I played with this for a long while, but see here: quarto is generating interfering enclosing containers when this approach is used.

[cderv]

Adding that knit_print method is usually a good way to have different behavior for inline vs in-chunk as there is inline argument set to TRUE when inline.

See more at https://cran.r-project.org/web/packages/knitr/vignettes/knit_print.html