Re: Tree sitter: Should *-ts-modes derive from a common base?

[Daniel Martín]

Phil Sainty <psainty@orcon.net.nz> writes:

> WRT
> https://emacs.stackexchange.com/questions/76400/how-do-i-check-if-the-current-buffer-has-a-treesit-parser
>
> I wondered whether derived-mode-p could conveniently establish
> some kind of base ts-mode, but that doesn't appear to be the case
> (or at least not for the examples I looked at).
>
> I was pondering something like this:
>
> (define-derived-mode prog-ts-mode prog-mode "Prog(TS)"
>   "Major mode for editing source code with tree-sitter support.")
>
> And then all the *-ts-mode derivatives of prog-mode changed like so:
>
> - (define-derived-mode cmake-ts-mode prog-mode "CMake"
> + (define-derived-mode cmake-ts-mode prog-ts-mode "CMake"
>
> The case I've spotted thus far which wouldn't work is the CSS modes,
> where we have this:
>
> (define-derived-mode css-base-mode prog-mode "CSS"
> (define-derived-mode css-mode css-base-mode "CSS"
> (define-derived-mode css-ts-mode css-base-mode "CSS"
>

Adding a common Tree-sitter base mode might be useful for some use cases
we'd need to describe in more detail, but I don't think it's the best
solution for the problem of checking if a Tree-sitter parser is
available or not.  For example, some major modes offer Tree-sitter
functionality without introducing a specific new Tree-sitter-based major
mode, so having a common inheritance wouldn't help here, I think.

Aren't (treesit-parser-list BUFFER) and (treesit-parser-language PARSER)
the best ways to check if Tree-sitter can be used in a particular
buffer, for a particular language?