Org writer: Use LaTeX style maths deliminators

[tecosaur]

Like Markdown, Org supports LaTeX fragments. However, while many Markdown flavours like the TeX-style $ / $$, as mentioned in the Org manual [1], Org works better with LaTeX-style \( \) / \[ \] delimiters. It also supports LaTeX environments (\begin{*} ... \end{*}) without any form of escaping, but that is best left to another patch.

[1]: https://orgmode.org/manual/LaTeX-fragments.html

[tarleb]

I don't understand. To me it seems that this PR removes support for TeX-style math (which *is* supported by at least the org HTML exporter), and duplicates support for LaTeX-style math. Can you explain more?

[tecosaur]

As it is currently, pandoc will export LaTeX maths snippets in a format that Org does not recognise as maths. The cause of this is mentioned in this point of that manual page:

To avoid conflicts with currency specifications, single ‘$’ characters are only recognized as math delimiters if the enclosed text contains at most two line breaks, is directly attached to the ‘$’ characters with no whitespace in between, and if the closing ‘$’ is followed by whitespace, punctuation or a dash. For the other delimiters, there is no such restriction, so when in doubt, use ‘(...)’ as inline math delimiters.

So, I can create a simple markdown file like

Say I have some $a$s and some $b$s. They are recognised as inline maths.

Clearly, these are parsed as maths elements:

~$ pandoc -f markdown -t latex inline-maths.md
Say I have some \(a\)s and some \(b\)s. They are recognised as inline maths.

Now, if I convert to Org

~$ pandoc -f markdown -t org inline-maths.md
Say I have some $a$s and some $b$s. They are recognised as inline maths.

Except, these are not maths elements in Org, due to the requirements quoted above, specifically

• "the closing ‘$’ is followed by whitespace, punctuation or a dash"

The form that Org better supports, and that acts as pandoc expects, is LaTeX-style delimiters.

[tarleb]

Thank you, I understand now. That was the information I was missing. We need to fix the tests before we can merge, could you take a look?

[tecosaur]

Glad I was able to clear that up 🙂 I've updated the test suite to match, hopefully this all looks good to you now.