Excluding the pattern for vim syntax highlighting

Question

I am trying to adjust the reStructured text syntax highlighting in vim. I have tried several vim regexes to get highlight working for below two examples, but I am unable to. If I use search/highlight function all below regexes do the job, but for highlighter (syn match) it is not working. Maybe I need to change syn match to something else?

This is the text example I am looking at in rst file:

.. item:: This is the title I want to highlight

    there is some text here which I do not care

.. item-matrix:: This is the title I want to highlight
    :source: XX
    :target: YY

Regexes that match the text:

[.+].*[:+] \zs.*
\(.. .*:: \)\zs.*

When putting that to syn match it does not work (.vim):

syn match rstHeading /[.+].*[:+] \zs.*/

I know I am close because above example matches for

..:: This is highlighted as rstHeading

Ingo Karkat Ingo Karkat · Accepted Answer · 2018-12-11T18:13:19

When integrating with an existing syntax script (here: $VIMRUNTIME/syntax/rst.vim), you need to consider the existing syntax groups. :syn list shows all active groups, but it's easier when you install the SyntaxAttr.vim - Show syntax highlighting attributes of character under cursor plugin. (I maintain an extended fork.)

On your example headings, I see that the .. item:: part is matched by rstExplicitMarkup, and the remainder (what you want to highlight) by rstExDirective.

Assuming that you want to integrate with (and not completely override) these, you need your syntax group to be contained inside the latter. This can be done via containedin=rstExDirective.

Another pitfall is that \zs limits the highlighting, but internally still matches the whole text. In combination with syntax highlighting, this means that the existing rstExplicitMarkup prevents a match of your pattern. If you use a positive lookbehind (:help /\@<=) instead, it'll work:

syn match rstHeading /\%([.+].*[:+] \)\@<=.*/ containedin=rstExDirective

Of course, to actually see any highlighting, you also need to define or link a highlight group to your new syntax group:

hi link rstHeading Title

Excluding the pattern for vim syntax highlighting

1 Answers