Shortcode extension that adds an executable code chunk

[dfalbel]

Description

Hi team!

I'm trying to create a quarto shortcode extension that adds inserts an executable code chunk into the document.
This is my current minimal example:

return {
  ['short'] = function(args, kwargs, meta) 
    local block = pandoc.CodeBlock("1 + 1")
    block.classes = pandoc.List({"r", "cell-code"})
    return block
  end
}

However whenever I return a pandoc.CodeBlock from the shortcode, I get an error:

Error running filter /Applications/quarto/share/filters/main.lua:
Inline, list of Inlines, or string expected, got table
        while retrieving function argument content
        while retrieving arguments for function Para
stack traceback:
        /Applications/quarto/share/filters/main.lua:16908: in function 'shortcodeResultAsBlocks'
        (...tail calls...)
        [C]: in ?
        [C]: in method 'walk'
        /Applications/quarto/share/filters/main.lua:165: in local 'checked_walk'
        /Applications/quarto/share/filters/main.lua:217: in function 'run_emulated_filter'
        /Applications/quarto/share/filters/main.lua:16783: in field 'Pandoc'
        /Applications/quarto/share/filters/main.lua:176: in function 'run_emulated_filter'
        /Applications/quarto/share/filters/main.lua:803: in local 'callback'
        /Applications/quarto/share/filters/main.lua:817: in upvalue 'run_emulated_filter_chain'
        /Applications/quarto/share/filters/main.lua:852: in function </Applications/quarto/share/filters/main.lua:849>
stack traceback:
        /Applications/quarto/share/filters/main.lua:165: in local 'checked_walk'
        /Applications/quarto/share/filters/main.lua:217: in function 'run_emulated_filter'
        /Applications/quarto/share/filters/main.lua:16783: in field 'Pandoc'
        /Applications/quarto/share/filters/main.lua:176: in function 'run_emulated_filter'
        /Applications/quarto/share/filters/main.lua:803: in local 'callback'
        /Applications/quarto/share/filters/main.lua:817: in upvalue 'run_emulated_filter_chain'
        /Applications/quarto/share/filters/main.lua:852: in function </Applications/quarto/share/filters/main.lua:849>

Here's a repo with a minimal example: https://github.com/dfalbel/short

Is this something that should be possible with shortcodes? What am I doing wrong?

Thank you!

[cscheid]

I'm trying to create a quarto shortcode extension that adds inserts an executable code chunk into the document.

Even without going into your code, that's not going to work at all :( Lua filters happen after knitr has already executed.

[dfalbel]

Thanks @cscheid. Would it be possible eg, ojs chunks that don't require a previous execution engine?

[cscheid]

No, those are also "executable", and are handled before pandoc :(

Lua filters currently handle "evaluated content" (that's not a real term we use, but gives you the right mental model). Knitr, Jupyter, OJS, dot, mermaidjs are all determined before Pandoc. Effectively, things that are denoted like so:

(Block syntax)
```{$SOME_LANGUAGE_HERE}
code
```

(Inline syntax)
`{$SOME_LANGUAGE_HERE} code`

(knitr inline syntax)
`r code`

Are all handled before Pandoc is called.

[dfalbel]

Thank you!