Can I develop custom markdown render formats?

[MichelNivard]

Description

I see there are quarto extensions for specific formats, their allt typist/html/pdf is it possible to author extensions to output custom markdown formats?

[mcanouil]

I believe, you can extend all the outputs formats available in Quarto but it will likely be through Lua filters or post-render script while Typst, LaTeX, and HTML can use partials/templates.

[dcnorris]

Could you offer more guidance on the architectural thinking behind excluding Markdown formats from this mode of extension? Is there some reason why a custom format based on one of Pandoc's many Markdown output formats would constitute a poor design?

$ quarto create extension format:commonmark
? Extension Name › PubPeer
ERROR: The sub type commonmark isn't valid. Expected one of html, pdf, docx, revealjs, typst

My thought was to develop a PubPeer format (deriving from commonmark_x-smart as that gets pretty close to the desired output) incorporating a custom Lua filter to trim leftovers that PubPeer's rather austere Markdown won't accept. From the Quarto user's perspective (mine!), it would be convenient to develop a comment in an HTML format, but then switch to format: PubPeer once it was ready to post. But from what I gather thus far, it seems a custom Markdown writer might be the best-supported approach.

[cscheid]

Could you offer more guidance on the architectural thinking behind excluding Markdown formats from this mode of extension?

I think the answer is simple and not very satisfying: not enough hours in the day between the developers.

[dcnorris]

That's actually very helpful, thanks!