bug#72388: 31.0.50; Use tree-sitter-cuda grammar but with tree-sitter-cpp's font-lock/indentation rules

bug#72388: 31.0.50; Use tree-sitter-cuda grammar but with tree-sitter-cpp's font-lock/indentation rules

[Yuan Fu]

Originated from "Implementing cuda-ts-mode” on emacs-devel [1]. Basically we want to create a major mode for tree-sitter-cuda. Tree-sitter-cuda grammar is basically cpp grammar plus some cuda rules. So it makes sense to reuse cpp mode’s font-lock/indentation rules. But those rules directs to the ‘cpp grammar. A simple solution is to allow users to map one language to another; then when ever lisp tries to create or get a parser for lang A, lang B is used.

Yuan

[1] Message-ID: <v2a2js5ssoz7d3hquenaieubgmj263tz3ejbogordd5t3ys4v2@efpjojlxrlv4>

bug#72388: 31.0.50; Use tree-sitter-cuda grammar but with tree-sitter-cpp's font-lock/indentation rules

[Ergus via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Hi Yuan:

I am just trying to use the new treesit-language-remap-alist and so far
I understand your idea of how to make it work for the basics. But it is
not clear how can I use the new var to add the new syntax entries.

I mean, looking at the grammar:

https://github.com/tree-sitter-grammars/tree-sitter-cuda/blob/master/grammar.js

You can see that it is the inherited C++ syntax, with extra entries in
some fields (like _declaration_modifiers or delete_expression). For this
part the new variable may work perfectly.

However there are a few "new" entries like: kernel_call_expression,
kernel_call_syntax and launch_bounds that will need special handling.

What's your suggestion?

I mean, for the latest what we really need is to extend (partially
redefine) the c-ts-mode--indent-styles, c-ts-mode--keywords and so on.

Is that the intended approach?

Best,
Ergus

bug#72388: 31.0.50; Use tree-sitter-cuda grammar but with tree-sitter-cpp's font-lock/indentation rules

[Yuan Fu]

Hey Ergus, sorry for the delay.

> On Aug 12, 2024, at 4:10 PM, Ergus via Bug reports for GNU Emacs, the Swiss army knife of text editors <bug-gnu-emacs@gnu.org> wrote:
> 
> Hi Yuan:
> 
> I am just trying to use the new treesit-language-remap-alist and so far
> I understand your idea of how to make it work for the basics. But it is
> not clear how can I use the new var to add the new syntax entries.
> 
> I mean, looking at the grammar:
> 
> https://github.com/tree-sitter-grammars/tree-sitter-cuda/blob/master/grammar.js
> 
> You can see that it is the inherited C++ syntax, with extra entries in
> some fields (like _declaration_modifiers or delete_expression). For this
> part the new variable may work perfectly.
> 
> However there are a few "new" entries like: kernel_call_expression,
> kernel_call_syntax and launch_bounds that will need special handling.
> 
> What's your suggestion?
> 
> I mean, for the latest what we really need is to extend (partially
> redefine) the c-ts-mode--indent-styles, c-ts-mode--keywords and so on.
> 
> Is that the intended approach?

Yeah, you can define your own cuda-indent-styles by grabbing c-ts-mode—indent-styles and adding your rules on top of it, something like

(append your-styles
        (c-ts-mode--indent-styles 'c++))

For font-lock, something like

(append (treesit-font-lock-rules
         :language 'cuda
         :faeture 'xxx
         '(queries))
        (c-ts-mode--font-lock-settings 'c++))

The new treesit-language-remap-alist will ensure that even though the config you borrow from c-ts-mode calls for c++, Emacs will actually use cuda grammar in your major mode.

Yuan