Updated Check for Math Zone

[Konfekt]

For reference: since the new syntax highlighting, a Vimscript function InMathZone() that checks whether the cursor is in a math zone now has to take account of the new highlighting groups texMathRegions (in addition to the built-in ones texMathZones), that is,

  let s:mathzones  = '\%(texMathZone\%([A-L]S\?\|[V-Z]\)\|texMathRegion\%(\|Ensured\|Env\|EnvStarred\|X\|XX\)\)'
  let s:textzones = 'texMathText\%(\|Arg\)'
  function! InMathZone()
    let ids   = reverse(map(synstack(line('.'), max([col('.') - 1, 1])), 'synIDattr(v:val, ''name'')'))
    let first = match(ids, '^' . s:mathzones . '\|' . s:textzones . '$')
    return (first >= 0 && match(ids[first], '^' . s:textzones . '$') == -1)
  endfunction

Edit: Take account of text zones in math zones.

[lervag]

This function is not necessary, because it is already available from vimtex directly: vimtex#syntax#in_mathzone. I know it is not documented and so it is not surprising that you (and generally people) don't know of it, but since you are posting this issue I thought it was OK to mention it :)

[lervag]

Btw: With Vimtex v2, there is no such thing as "built-in texMathZones".

[Konfekt]

Yes, sorry for the confusion, built-in referred to built into Vim, in $VIMRUNTIME. The use case in mind was a function to define abbreviations that only expand in Math zones, independent of the used TeX plug-in, such as

inoreabbrev <expr> ==     InMathZone() ? '\equiv' : '=='

[lervag]

Btw, your function could be greatly simplified:

function! InMathZone()
  return match(map(synstack(line('.'), max([col('.') - 1, 1])),
        \ 'synIDattr(v:val, ''name'')'),
        \ '^texMath\%(Zone\|Region\)')
        \ >= 0
endfunction

I don't see any region of matching the final part, as I think the prefix texMathZone and texMathRegion should match all the relevant groups.

[Konfekt]

Yes, the definition is pedantic in limiting exactly to the existing syntax groups as it is unlikely that a future syntax group matching the prefix will not be a math zone.

[Konfekt]

If returning to the naming of Zone instead of Region, then for all practical ends the regular expression '^texMathZone would suffice. It would also correspond to the naming of vimtex#syntax#in_mathzone.