Re: Disable tree-sitter font-locking for smaller ranges

[Yuan Fu]

> On Oct 16, 2022, at 3:32 AM, Theodor Thornhill <theo@thornhill.no> wrote:
> 
> 
> Hi Yuan!
> 
> I've been trying to tweak the font-locking for tree-sitter in
> js/ts-mode, and I'm still struggling with the template strings.  Is
> there a way to _disable_ font-locking for smaller ranges?
> 
> Let's say you have this string:
> ```
> `Some string with ${5+5} many template substitutions ${foo().bar().baz()}`;
> ```
> 
> This string will match something like:
> ```
> (template_string (template_substitution) :*)
> ```
> 
> If you use this as a query:
> ```
> (template_string) @font-lock-string-face
> ```
> 
> Everything inside the string is in string-face.
> 
> If you add
> ```
> (template_substitution
> "${" @font-lock-constant-face
> (_)
> "}" @font-lock-constant-face)
> ```
> 
> You get font-locking in the ranges inside the squigglies, as expected.
> However, if there isn't defined any rules for say, "(), . []" etc, the
> template_string capture will bleed into the substitution, because its
> range suggests it should.  It would be nice to say something like:
> 
> ```
> (defvar fonts ()
>  (treesit-font-lock-rules
>     :language 'tsx
>     :override t
>     :feature 'basic
>     '((template_string (_):* @disabled) @font-lock-string-face 
>       (template_substitution ["${" "}"] @font-lock-constant-face)))
> ```
> 
> to ensure that whatever is inside the wildcard match will _not_ be
> considered for the string face, but whatever is still inside the bigger
> range will.  Is this currently possible?  If not, is
> it possible to add?  I guess I could make a function that would remove
> the range, but that seems fiddly and error prone.
> 
> I've tried fiddling with the :feature flag in 'treesit-font-lock-rules',
> but I never found a combination that did what I wanted.
> 
> Adding a small image of a stupid snipped just to make the point more visual

The image you attached looks perfectly fine to me. Do you not want to font-lock 
what’s inside a substitution? I’m not exactly sure what result you want to 
archive.

If you don’t want font-lock in substitutions, you can put 

>  '((template_string) @font-lock-string-face 
>       (template_substitution ["${" "}"] @font-lock-constant-face))


After all other queries, and mark these two with :override t. That should do it.

Also, when I was browsing tsx’s grammar file, I didn’t find definition of 
template_substitution at all. That means at least some part of js and tsx’s 
grammar are not interchangeable.

Yuan