Markdown reader: add extension for GitHub wiki's internal link syntax [[page name]]

[ferventcoder]

Forgive me if this has already been noted as an issue but I did a bit of searching through issues and online and didn't turn up with anything.

I'm on the latest version of Pandoc (1.17.0.2) and I'm attempting to use markdown_github to convert to HTML. I'm noticing that Pandoc does not convert links that look like the following:

• [[example link|MarkdownPage]]
• [[MarkdownPage]]

It's possible we are using outdated constructs, but GitHub has supported this for years. I noticed that Sublime supports the second but not the first with it's regular markdown preview tool.

The command I'm running:
pandoc --from markdown_github+simple_tables+native_spans+native_divs+multiline_tables --to html5 [..snip..]

Is this something that could be added for conversion? Or is there an extension that already does this that I may have missed?

[jgm]

The syntax is documented here.
However, I believe it only works for GitHub wikis, and not in other contexts (e.g. bug reports). Proof:
[[example link|MarkdownPage]]

It would be worth adding an extension for this.

[ferventcoder]

Thanks @jgm! Pandoc is pretty amazing! I'll admit I haven't read the source, but this is the regex I'm using to do this conversion now:
https://github.com/ferventcoder/chocolatey.org/blob/45765dd4cc2f9d2675d0f48fd4dd60669afb8bf8/UpdateDocumentation.ps1#L12-L24

[jgm]

Re-opening, on the realization that we really need the parser in a commonmark extension (so it can be used withgfm). Once that is available, we could also add a parser to pandoc's markdown reader, but I don't want to just add it to the latter; it will cause too much confusion.

[jgm]

The tests and extension module work in #6458 will be useful when the commonmark-hs extension is available.

[jgm]

The wikilinks extension is available now for commonmork-hs:
https://hackage.haskell.org/package/commonmark-extensions-0.2.1.2/docs/Commonmark-Extensions-Wikilinks.html
So now there is no obstacle to supporting this syntax.

[jgm]

Note that in commonmark-hs we support two forms of the extension,
wikilinks_title_before_pipe
wikilinks_title_after_pipe
since some markdown wiki formats put the title before the pipe (like GitHub) and others after.
It would be useful to support both in pandoc.

[jgm]

I think it would be good to support multiple markdown wikilink syntaxes, not just the one used in GitHub wikis, but those used in popular note taking applications like obsidian and roam.
The problem is, these are all slightly different.
One difference is whether the title comes before or after the pipe.
Another is whether the URL is munged somehow (e.g. in GitHub wikis spaces are converted to - and other symbols are encoded).
Supporting the two pipe positions seems feasible, but if we try to support every other dimension of variation, it quickly gets out of hand.
Hence I'd favor supporting just the two pipe positions, and encoding spaces as well as other symbols in the URL; users who want to generate correct links for GitHub wikis would then need to use a small filter to change these spaces to dashes. Not sure though.

[edrex]

Emanote (a publishing tool compatible with Obsidian and Foam) has its own implementation of the [[Page|Label]] syntax used by most wikis but it would be nice to switch to an upstream one.

https://github.com/srid/emanote/blob/master/src/Emanote/Pandoc/Markdown/Syntax/WikiLink.hs

[mebu83]

Thanks so much! This is awesome!

[anutator]

Please add mediawiki images conversion:
![[image1.png]]