bug#58711: Treesit hangs when calling treesit-search-forward

[Wilhelm Kirschbaum <wilhelm@floatpays.co.za>]

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Full implementation here:
https://github.com/wkirschbaum/elixir-mode/blob/main/heex-mode.el

On Thu, 10 Nov 2022 at 21:03, Wilhelm Kirschbaum <wilhelm@floatpays.co.za>
wrote:

> forward-sexp works well with the below code, but when calling
> treesit-node-prev-sibling it will traverse up the list, which is then
> breaking backward-up-list when defining forward-sexp in the major mode.
>
> (defun heex--treesit-largest-node-at-point ()
>   "Find the largest node at point."
>   (save-excursion
>     (forward-comment (point-max))
>     (let ((node-list
>            (cl-loop for node = (treesit-node-at (point))
>                     then (treesit-node-parent node)
>                     while node
>                     if (eq (treesit-node-start node)
>                            (point))
>                     collect node)))
>       (car (last node-list)))))
>
> (defun heex--treesit-backward-sexp ()
>   "Forward sexp for Heex using treesit."
>   (let* ((largest-node (heex--treesit-largest-node-at-point))
>          (sibling (treesit-node-prev-sibling largest-node)))
>     (when sibling
>       (goto-char (treesit-node-start sibling)))))
>
> (defun heex--treesit-forward-sexp ()
>   "Forward sexp for Heex using treesit."
>   (let* ((largest-node (heex--treesit-largest-node-at-point))
>          (sibling (treesit-node-next-sibling largest-node)))
>     (when sibling
>       (goto-char (treesit-node-start sibling))
>       (forward-comment (- (point-max))))))
>
> On Thu, 10 Nov 2022 at 10:14, Yuan Fu <casouri@gmail.com> wrote:
>
>>
>>
>> > On Nov 9, 2022, at 10:44 PM, Wilhelm Kirschbaum <
>> wilhelm@floatpays.co.za> wrote:
>> >
>> > I finally had some time to have a look. I don't see any more issues,
>> thank you for the fantastic work on this. The defun-type-regexp is not
>> enough to identify a defun in elixir this is the query I am using currently:
>> >
>> > (defvar elixir--treesit-query-defun
>> >   (let ((query `((call
>> >      target: (identifier) @type
>> >      (arguments
>> >       [
>> >        (alias) @name
>> >        (identifier) @name
>> >        (call target: (identifier)) @name
>> >        (binary_operator
>> >         left: (call target: (identifier)) @name
>> >         operator: "when")
>> >        ])
>> >      (:match ,elixir--definition-keywords-re @type)
>> >      ))))
>> >     (treesit-query-compile 'elixir query)))
>> >
>> > Regex will work in most cases I guess, but does not really deal with
>> more complex queries for more complex cases like in elixir as there is not
>> one type which is always the defun. elixir relies heavily on macros and
>> different defun macros can be defined on the fly.
>>
>> You can try the following procedure: use a regex to find the
>> next/previous call, then perform some check on whether it’s indeed a defun,
>> if not, keep searching for the next/previous call.
>>
>>
>> > Maybe if there is an option for using either a regex or a function?
>>
>> Yes, instead of a regex you can pass a predicate function.
>>
>> >
>> > I am also not sure how forward-sexp can work with the current
>> treesit-search-forward-goto function as it does not take into consideration
>> the level. Is there perhaps a way to move forward/backward, but do not jump
>> to parents or children?
>>
>> If you want to move in the same level, perhaps you can use
>> treesit-next/prev/sibling?
>>
>> Yuan
>
>

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