Differences between KaTeX and MathJax (underscore in text math)

[rowanc1]

It looks like if you have \text{something_with_underscores} in a math block, this works in MathJax and Jupyter, but with fail in MyST. This is due to the differences between LaTeX/KaTeX/MathJax:

• Katex does not parse but MathJax does KaTeX/KaTeX#1676
• Bug: underscore not handled correctly in \text{} macro mathjax/MathJax#1770

Apparently this is actually incorrect LaTeX, but has been introduced as acceptable by MathJax. I think that MyST should parse this (via regexp) and patch it (and or react to the error, and fix it at that stage). This would support, for example, numpy-tutorials to have a smoother onboarding experience.

cc @melissawm @fperez (Note also that the numpy-tutorials content currently doesn't render in VSCode becase of this!)

[melissawm]

Thanks, @rowanc1 ! We got around it by escaping the underscore, but would definitely be great to see a fix.