>>>>> Are there any plans to add treesitter support for hideshow, it seems easy
>>>>> enough to do and also very helpful, especially for langs that don't
>>>>> excessively use parens, such as python
>>>>
>>>> Indeed, it's easy to do this.  You just need to override
>>>> hs-find-block-beginning-func, hs-find-next-block-func, etc.
>>>> with treesit functions like 'treesit-outline-search'.
>>>
>>> Ah I see, then I think treesit.el should contain code for this, because
>>> this seems extremely useful task that would not make sense if each tree
>>> sitter based major mode was to implement this separately
>>
>> Or hideshow code for treesit could be in hideshow.el as well.
>> The reason why 'treesit-outline-search' was added to treesit.el
>> was because treesit.el already contained imenu support.  But
>> imenu support could be in imenu.el as well.
>
> Is there a preferred way to handle this treesit wise. I know some packages
> (eg imenu) require major modes to define their support for it, but others
> like ispell do it themselves. I personally thing the latter would be better
> in this case.

I looked at hideshow.el and found such a list:

(defvar hs-special-modes-alist
  (mapcar #'purecopy
  '((c-mode "{" "}" "/[*/]" nil nil)
    (c-ts-mode "{" "}" "/[*/]" nil nil)
    (c++-mode "{" "}" "/[*/]" nil nil)
    (c++-ts-mode "{" "}" "/[*/]" nil nil)
    (bibtex-mode ("@\\S(*\\(\\s(\\)" 1))
    (java-mode "{" "}" "/[*/]" nil nil)
    (java-ts-mode "{" "}" "/[*/]" nil nil)
    (js-mode "{" "}" "/[*/]" nil)
    (js-ts-mode "{" "}" "/[*/]" nil)
    (lua-ts-mode "{\\|\\[\\[" "}\\|\\]\\]" "--" nil)
    (mhtml-mode "{\\|<[^/>]*?" "}\\|</[^/>]*[^/]>" "<!--" mhtml-forward nil)

But this is useless for tree-sitter.

Line-oriented treesit-outline-search relied on treesit-simple-imenu-settings
that defines header lines for imenu.  And every ts-mode sets own value of
treesit-simple-imenu-settings.  But this can't be used for hideshow.

So whoever will implement hideshow support for treesitter
will need to design a setting like buffer-local
treesit-simple-imenu-settings for ts-modes.