Re: Questions about tree-sitter

[Yuan Fu <casouri@gmail.com>]

> On Sep 8, 2023, at 4:53 AM, Augustin Chéneau (BTuin) <btuin@mailo.com> wrote:
> 
> Le 06/09/2023 à 06:07, Yuan Fu a écrit :
>> I added local parser support to master. If everything goes right, you just need to add a :local t flag in treesit-range-rules. Check out the modified bision-ts-mode.el that I hacked up for an example. BTW, it’s vital that you define treesit-language-at-point-function for a multi-language mode.
>> Yuan
> 
> Thanks a lot!
> 
> I did some tests and it's working pretty well.

Awesome!

> Do you think it's a good idea to add a prefix to bison feature names in font-lock settings to avoid conflicts with C names (as I did)?

I should add some way to distinguish between languages in feature name list. The tricky part is to make it backward compatible and not too confusing and still convenient to use.

> I have a few issues though:
> 
> - I first defined `treesit-language-at-point-function` using
> `treesit-node-at`.  However, `treesit-node-at` itself uses
> `treesit-language-at-point-function` which causes an infinite recursion.
> So I instead used `treesit-local-parsers-at` to check if a local parser is used.  Is it a good solution?

No no, you should use the host langauge’s parser (bison) and see if point is in an undelimited_code_block, and return c or bison accordingly. I’m highlight this in the docstring, thanks.

For now, you can use something like

(mapcar (lambda (rule)
             (list (nth 0 rule)
                   (nth 1 rule)
                   (intern (format "js-%s" (nth 2 rule)))
                   (nth 3 rule)))
           js--treesit-font-lock-settings)

to add prefix to c-ts-mode’s font-lock rules’ features.

> 
> - When I try to indent C code by using c-ts-mode indent rules, I get the following error:
> 
> Debugger entered--Lisp error: (wrong-type-argument treesit-node-p #<treesit-parser for c>)
>  treesit-node-parser(#<treesit-parser for c>)
>  treesit--indent-1()
>  treesit-indent-region(1075 1176)
>  indent-region(1075 1176)
>  indent-for-tab-command(nil)
>  funcall-interactively(indent-for-tab-command nil)
>  call-interactively(indent-for-tab-command nil nil)
>  command-execute(indent-for-tab-command)
> 
> There seems to be a mistake in `treesit--indent-1` in the `cond` at the line `(local-parsers (car local-parsers))`, since a parser is returned while it should be a node.

Thanks, I fixed that on master. And c-ts-mode’s feature list is a separate variable now.

Yuan