Re: Adding jsdoc support to js-ts-mode

[Dmitry Gutov <dmitry@gutov.dev>]

Hi Damien,

On 07/06/2024 10:55, Damien Cassou wrote:
> Currently, jsdoc comments are not recognized in js-ts-mode (see
> before.png screenshot attached). I'm trying to fix that (see current
> status in after.png).

I guess you're using the jsdoc tree-sitter grammar in addition to Lisp 
code. The alternative would be pure-regexp matching, but this might be 
easier indeed.

> As you can see in the after.png screenshot, there is no face applied to
> the comment markup "/*" and "*". I would like to see
> `font-lock-comment-face` applied. I haven't written any code to do that
> because I don't know how to apply a face to characters that are not
> treesit nodes. Can someone please help?

You could try adding a custom rule which applies highlights to specific 
ranges. The function to call is treesit-fontify-with-override.

See its usage examples in the tree - most of them still deal with nodes, 
but you just need to pass the character positions, which can be 
calculated in different ways.

> The code to get after.png is below. If you have any feedback, that would
> be greatly appreciated. When everything is fine, I will submit a patch.
> 
> Please make sure I'm on CC when replying as I'm not subscribed to the
> mailing list.
> 
>    (defun js-ts-language-at-point (point)
>          "Return the language at POINT."
>          (let ((node (treesit-node-at point 'javascript)))
>            (if (and (treesit-ready-p 'jsdoc)
>                     (equal (treesit-node-type node) "comment")
>                     (string-match-p
>                      (rx bos "/**")
>                      (treesit-node-text node)))
>                'jsdoc
>              'javascript)))
> 
> 
> To be added to js-ts-mode body:
> 
>    (setq treesit-range-settings
>          (treesit-range-rules
>           :embed 'jsdoc
>           :host 'javascript
>           `(((comment) @capture (:match ,(rx bos "/**") @capture)))))

Nice.

>    (setq-local treesit-language-at-point-function #js-ts-language-at-point)

Seems like this needs ' after #.