Advice on treating HTML as a first-class output format for LaTeX

[omentic]

Hi all, I've got a nice setup for generating PDFs using Pandoc. Thanks to Pandoc Flavoured Markdown, I can write my prose in Markdown, have inline math with $$, and even write LaTeX with {=latex} blocks. By using the header-includes option in YAML front matter I can even get arbitrary packages working.

This is all very nice for outputting PDFs. I would like to output HTML as well, though. A lot of stuff works out of the box (MathML support is very nice). But more complicated things and especially anything using packages is silently dropped -- because there's no obvious way to render them.

I would like to have Pandoc render anything in a \begin block as an SVG, to be included in the raw outputted HTML. This would be really nice as I think I could use the div blocks feature to style and size them when desired. Specifically, I would like Pandoc to be able to render the following to HTML (in approx. order of priority):

• the forest package for syntactic trees
• the bussproof package for proof trees (this works with --mathjax alr! but i use mathml)
• tables via \begin{center}
• tixz images

How might I go about doing this? Are there setups or things that exist for this? I have heard some things about filters, but I'm not sure whether that would be enough. Maybe filters paired with modifying the default template? Any advice would be appreciated :-)

[tarleb]

A partial answer: for centered context, I suggest to use fenced divs in Markdown, and then a pandoc Lua filter to generate the desired output, e.g.,

function Div (div)
  if div.classes:includes 'center' then
    return {pandoc.RawBlock('latex', '\\begin{center}'} .. div.content .. {pandoc.RawBlock{'latex', '\\end{center}'}
  end
end

which should convert input like

::: {.center}
foo
:::

to

\begin{center}

foo

\end{center}

The HTML-output of fenced divs can easily be styled via CSS.

TikZ images are handled by the diagram filter.

I don't have any immediate ideas for forest and bussproof, but it might make sense to add them to diagram. Feel free to open a feature request over there.

You may also be interested in the pandoc-based tool quarto, as it has a few more layout options built-in.

[omentic]

Interesting! This diagram filter works great for TikZ, thank you. I might look into adding forest and bussproof support then...

Can I ask, why does diagram require blocks to be labeled with ex. {.tikz} instead of {=latex}? Is it to reliably detect the environment? (I haven't yet read the diagram source`, so maybe this is answered there.)

I mildly prefer {=latex} since that gets me syntax highlighting elsewhere, but I'd imagine that you had your reasons...

[omentic]

I opened up a pull request for forest and bussproof. It'll probably need some iteration.

[tarleb]

Can I ask, why does diagram require blocks to be labeled with ex. {.tikz} instead of {=latex}? Is it to reliably detect the environment?

The main reason is that code blocks can have attributes, but raw blocks don't, and I wanted those. It's interesting that your editor has better support for raw blocks than for code blocks, it's the other way around for me.

Thanks for the PRs, I hope to take a look early next week!