Re: Treesitter injection support

[Yuan Fu]

> On Jan 2, 2025, at 6:48 AM, Pranshu Sharma <pranshu@bauherren.ovh> wrote:
> 
> 
> I'm making cperl clone using treesitter, and have done all of
> highlighting apart from regex and pod.
> 
> For regexp, I need different grammer to highlight it, and using the
> treesit-parser-set-included-ranges doesn't work.  An example:
> 
> preq knowledge:
> 
> 's/bi?g/small/' replaces instances of 'bg' and 'big' with 'small', and
> 's/([0-9]+)/$1 + 1/e' incrimental all number (the 'e' at the end tells
> perl to evaluate the code).
> 
> the parse tree of 's/([0-9]+)/$1 + 1/e' is:
> (substitution_regexp operator: s '
>     content: (regexp_content not-interpolated not-interpolated) '
>     (replacement
>      (scalar $ (varname)))
>     ' modifiers: (substitution_regexp_modifiers))
> 
> (replacement) needs to be conditionally parsed as perl over here because
> of the 'e' modifier.  Now I cannot use range for this, because say if I
> had:
> 
> 's/(([0-9]+),)+/s#([0-9]+)#$1 + 1#e/e;'
>                           ^^^^^^          Perl code
>                ^^^^^^^^^^^^^^^^^^^        Perl code
> 
> 
> The replacement contains another replacment which contains perl code, so
> it overlaps
> 
> So I won't have any way to highlight.  It seems making this work could
> be possible using nested parsers with their own setting each using own
> local treesit-range-settings, but this seems really hard with
> treesit-range-settings being a buffer local variable.
> 
> -- 
> Pranshu Sharma <https://p.bauherren.ovh>

Ok, so the problem is nested parsers. I don’t think the overlap would cause any 
problem. Right now treesit-range-settings can only give you one nested layer. 
I’ll need to make it support nesting a parser inside a local parser of the same 
language. I’ll work on that once I wrap up the thing I’m working on right now 
:-)

Yuan