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

[Yuan Fu <casouri@gmail.com>]

> On Nov 10, 2022, at 12:43 PM, Wilhelm Kirschbaum <wilhelm@floatpays.co.za> wrote:
> 
> Given the following code
> 
>  <.foo>  ;; component, start_component
>  <bar>  ;; tag, start_tag
>   </bar>;; [cursor here 1)] end_tag 
> </.foo> ;; [cursor here 2] end_component
> 
> and ast
> 
> (fragment [0, 0] - [5, 0]
>   (component [0, 0] - [3, 7]
>     (start_component [0, 0] - [0, 6]
>       (component_name [0, 1] - [0, 5]
>         (function [0, 2] - [0, 5])))
>     (tag [1, 2] - [2, 8]
>       (start_tag [1, 2] - [1, 7]
>         (tag_name [1, 3] - [1, 6]))
>       (end_tag [2, 2] - [2, 8]
>         (tag_name [2, 4] - [2, 7])))
>     (end_component [3, 0] - [3, 7]
>       (component_name [3, 2] - [3, 6]
>         (function [3, 3] - [3, 6])))))
> 
> I do not know how to reliably move from cursor position 1 to start of <bar> and from cursor position 2 to start of <.foo>

The snippet below should take you to the corresponding open tag.

(let ((end-node (treesit-search-forward-goto
                 (treesit-node-at (point))
                 (rx (or "end_tag" "end_component" "end_slot")) t t)))
  ;; Go to the corresponding start tag.
  (goto-char (treesit-node-start (treesit-node-parent end-node))))

> 
> as (treesit-search-forward (treesit-node-at (point)) (rx (or "end_tag" "end_component" "end_slot")) t) on position 1 will not look backwards, but find the <./foo> end_component. 
> 
> if i am at the point after the node, how do I find the node before the point? once we have the node before the point we can find the correct parent and then find the prev sibling to goto. 
> 
> Hope this makes sense. 

Yeah, if there is a function that gives you the node right before point, treesit-search-forward would work as expected. I’ll see how to add this functionality.

Yuan