better pandoc support

[jirib]

Hi,

it would be nice to have better pandoc integration as I feel commonmark has limitations and pandoc markdown can do much more things. Examples:

• ability to have TOC made by pandoc, just like asciidoctor support (enableTOC: false - to pass --toc to pandoc, preserveTOC = false - to override pandoc TOC html code <nav id="TOC" role="doc-toc">with hugo .TableOfContent variable; it would be probably nice also to be able to define css selector to find pandoc TOC as one could change pandoc template.
• extra args, eg. to define --template <file> or --data-dir <dir> ...

[jwflory]

If better Pandoc support means that my toc appear in AsciiDoc-based HTML, that would be a big win. I see it appear in my local previews with the Asciidoctor.js extension, but it would be nice for the table-of-contents attribute to make it to the generated HTML by Hugo for my site.

[jirib]

If better Pandoc support means that my toc appear in AsciiDoc-based HTML, that would be a big win. I see it appear in my local previews with the Asciidoctor.js extension, but it would be nice for the table-of-contents attribute to make it to the generated HTML by Hugo for my site.

Have you tried this?

By default, Hugo removes the table of contents generated by Asciidoctor and provides it through the built-in variable .TableOfContents to enable further customization and better integration with the various Hugo themes. This option can be set to true to preserve Asciidoctor’s TOC in the generated page.
-- https://gohugo.io/content-management/formats/#external-helper-asciidoctor

[jirib]

BTW, I more wanted to use pandoc markdown with all its extensions, not just TOC... And IIUC, with pandoc one could write content for hugo in latex for example provided that the file extension is pandoc.

And passing extra vars... I have not read hugo source but IIUC it passes stdin to pandoc and it sets argument to --mathjax. This way pandoc does not know what file hugo read, it would be great to be able to pass somehow name of the file to hugo as variable. Let's take an odd example - people writing content in ODT :) A frontmatter would be in a file with pandoc extension, there would be similar file but with ODT extension. With little pandoc wrapper one could do:

# pandoc wrapper without filtering of input args
#!/bin/bash

set -o pipefail
set -e

# TODO: process args, filter -V filename...
filename=/tmp/Untitled_2.pandoc
newargs=$@ # rest of original args
tmpfile=$(mktemp)

trap "rm -f ${tmpfile}" EXIT
cat > ${tmpfile}

exec /usr/bin/pandoc -f odt -t html5 --toc --template /tmp/templ \
     --metadata-file ${tmpfile} ${filename%.pandoc}.odt ${newargs}

# see what in ODT file

$ /usr/bin/pandoc -f odt -t commonmark /tmp/Untitled_2.odt 
Heading 2
---------

### Heading 3

Text[1]

[1] Footnote

# simulation of hugo using pandoc which converts an ODT file

$ pandoc -V filename=/tmp/Untitled_2.pandoc --mathjax < /tmp/Untitled_2.pandoc 
<h1 class="title">hello world!</h1>
<h2 id="heading-2">Heading 2</h2>
<h3 id="heading-3">Heading 3</h3>
<p>Text<a href="#fn1" class="footnote-ref" id="fnref1" role="doc-noteref"><sup>1</sup></a></p>
<section class="footnotes" role="doc-endnotes">
<hr />
<ol>
<li id="fn1" role="doc-endnote"><p>Footnote<a href="#fnref1" class="footnote-back" role="doc-backlink">↩︎</a></p></li>
</ol>
</section>

I.e. an ability to pass {{.File.LogicalName}} as pandoc variable, for example.

[yaxu]

I had a look at making pandoc more configurable today, the first time I've written any go code but getting somewhere - I managed to get citeproc support working.

I noticed the mathjax support doesn't seem to actually work.. Pandoc does the processing but mathjax itself isn't loaded. I'm not a TeX math user so left that as-is.

[yaxu]

As far as I can tell, the YAML header doesn't get passed to pandoc, is that intentional? I can add more parameters to this PR #8610 , but it would be nice to set things in the header too.

[jirib]

FYI PR #7529

[yaxu]

Ah thanks, somehow I didn't look for previous PRs and now I see there is this one too: #4800

PR #7529 looks great, far more developed than mine. I think being able to configure the existing pandoc support is a really important feature for a lot of people. It would be great to see this merged.

[danmackinlay]

In case anyone wants citation support right now you can use blogdown which invokes pandoc in a separate pass and bypasses hugo's hardcoded pandoc rendering.