Support distinguishing different cases of math environment using different group

[pilgrimlyieu]

Use different groups for texMathZones to make it possible to distinguish them. See also #2397.

Here are currently supported cases (see :help vimtex-syntax-reference, table 3):

  GROUP                    DEFAULT        EXAMPLE
  ----------------------------------------------------------------------------
  texMathZone              Special        \( HERE \); \[ HERE \]
  texMathZoneX             texMathZone    $ HERE $
  texMathZoneXX            texMathZone    $$ HERE $$

Notice that we can't distinguish \( Inline Math \) and \[ Display Math \] through, since they are both texMathZone.

[lervag]

Perhaps we could use something like this:

GROUP	DEFAULT	EXAMPLE
texMathZoneLI	Special	\( here \)
texMathZoneLD	Special	\[ here \]
texMathZoneTI	texMathZone	$ here $
texMathZoneTD	texMathZone	$$ here $$

The idea behind these names is that the L implies the LaTeX shorthand, whereas the T implies the TeX shorthand. Further, the I is for "inline" and D is for "display". This is consistent with how these forms are explain in e.g. the wiki LaTeX book.

@clason do you have any thoughts on this? Ideas for more consistent naming, perhaps?

[clason]

Hmm, I'd prefer if the current behaviour wouldn't change (all math zones link to texMathZone, which links to Special).

Otherwise the naming is sound (and better than X, XX); I just worry a bit about compatibility with the builtin tex syntax file -- will this lead to a huge regression with common colorschemes? (But are there even any with specific tex highlight groups?)

Will you use special groups for the delimiters themselves then?

[lervag]

Hmm, I'd prefer if the current behaviour wouldn't change (all math zones link to texMathZone, which links to Special).

Sorry, here's an adjusted suggestion that should make more sense:

GROUP	DEFAULT	EXAMPLE
texMathZone	Special	N/A
texMathZoneLI	texMathZone	\( here \)
texMathZoneLD	texMathZone	\[ here \]
texMathZoneTI	texMathZone	$ here $
texMathZoneTD	texMathZone	$$ here $$

Will you use special groups for the delimiters themselves then?

The delimiters will still all link to texMathDelimZone, of course.

Otherwise the naming is sound (and better than X, XX); I just worry a bit about compatibility with the builtin tex syntax file -- will this lead to a huge regression with common colorschemes? (But are there even any with specific tex highlight groups?)

I don't think so, but I have to admit I don't know. But then, this change should make it really easy for colorscheme creators to adjust their rules, right?

[clason]

The delimiters will still all link to texMathDelimZone, of course.

I meant, will you add texMathDelimZoneTD and friends? (I assume yes, but just to make it explicit.)

I don't think so, but I have to admit I don't know. But then, this change should make it really easy for colorscheme creators to adjust their rules, right?

Yes, it's not hard to adapt at all; just trying to come up with possible complaints about this change.

[lervag]

The delimiters will still all link to texMathDelimZone, of course.

I meant, will you add texMathDelimZoneTD and friends? (I assume yes, but just to make it explicit.)

I don't see why not. If we link them to a common one, things will not change for anyone, except it allows more flexibility for people who might want it.

Updated suggestion:

GROUP	DEFAULT	EXAMPLE
texMathZone	Special	N/A
texMathZoneLI	texMathZone	\( here \)
texMathZoneLD	texMathZone	\[ here \]
texMathZoneTI	texMathZone	$ here $
texMathZoneTD	texMathZone	$$ here $$
texMathDelimZone	texDelim	N/A
texMathDelimZoneLI	texMathDelimZone	\( and \)
texMathDelimZoneLD	texMathDelimZone	\[ and \]
texMathDelimZoneTI	texMathDelimZone	$ and $
texMathDelimZoneTD	texMathDelimZone	$$ and $$

[lervag]

Notice, with these suggestions, it would be easy to check if one is inside an inline environment with vimtex#syntax#in('texMathZone[LT]I'), or inside any of the math zones with vimtex#syntax#in('texMathZone').

[lervag]

Done; I've updated the code and the docs, as well as the related wiki entry. Let me know if there is something that is not working as expected!

(I will make sure this gets some attention in the next release notes.)