TeX syntax highlighting inside Markdown blockquotes

[lutalli]

I use Markdown to write blogs and recently I'm planning to utilize blockquotes (lines that start with >) in my math articles for theorems, definitions, etc. That means I need to work with TeX equations inside blockquotes a lot, and I want them to be highighted properly. (Maybe this is rather a niche setup?)

Normally blockquotes are just completely grayed out for me, as their highlight group is linked to Comment. Using Treesitter, I managed to restore Markdown inline syntax inside blockquotes (bold, italic, etc.) - see this issue. But I still can't get TeX equations inside blockquotes to be highlighted. Any ideas?

[lervag]

If you use Treesitter, then VimTeX syntax highlighting is simply not compatible. That is, to my knowledge, you can't use regular built-in (legacy) Vim/Neovim syntax rules in a nested fashion when you use Treesitter for your highlighting.

If you want to use VimTeX for highlighting in Markdown, then you need to use the legacy syntax method for Markdown and specify rules with nested highlighting that includes tex highlighiting. This means you need to avoid enabling Treesitter for Markdown (at least for highlighting).

Exactly how to do it depends on whether you are using a plugin (like vim-markdown) or not. For vim-markdown, you could add after/syntax/tex.vim with something like this:

if exists('b:did_after_syntax_markdown') | finish | endif
let b:did_after_syntax_markdown = 1

syntax region mkdBlockquote start=/^\s*>/ end=/^\s*$/
  \ contains=mkdLink,mkdInlineURL,mkdLineBreak,@Spell,mkdMath

[lervag]

You might be interested in reading :help vimtex-faq-treesitter.

[lutalli]

Thanks for the quick reply! I do use vim-markdown and the code you provided works pretty well (with Treesitter disabled). I did try something similar before but it was not working for some reason.

The only issue now is that other Markdown markings inside blockquotes are not highlighted (though at this point it's not so important).

[lervag]

Thanks for the quick reply! I do use vim-markdown and the code you provided works pretty well (with Treesitter disabled).

Great, glad to hear it.

The only issue now is that other Markdown markings inside blockquotes are not highlighted (though at this point it's not so important).

Yes - to enable more items you need to add them to the contains=. You can use :Inspect to see what the group under your cursor is called, then you could try adding that group similar to how I added mkdMath. contains takes a comma separated list of groups with no white spaces.

[lutalli]

Oh, I was not aware! This works for me wonderfully:

if exists('b:did_after_syntax_markdown') | finish | endif
let b:did_after_syntax_markdown = 1

syntax region mkdBlockquote start=/^\s*>/ end=/^\s*$/
    \ contains=mkdLink,mkdInlineURL,mkdLineBreak,@Spell,mkdMath,
	\ htmlItalic,htmlBold,htmlBoldItalic,mkdCode,htmlTag,htmlEndTag

Besides this I can also use hi! link mkdBlockquote Normal to highlight blockquotes as normal text instead of grayed out comment, for example.

[lervag]

Yes, exactly. You're now mastering the ancient arts of the legacy Vim syntax highlighting 😅