Re: Code navigation for sh-mode with Tree-sitter

["João Paulo Labegalini de Carvalho" <jaopaulolc@gmail.com>]

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>
> Ok, I fianlly finished the defun navigation work, thanks to Alan’s
> suggestion, your experiment, and honorable sacrifices of my many brain
> cells. Now tree-sitter should give you both nested and top-level defun
> navigation for free, provided that the major mode sets
> treesit-defun-type-regexp. I’ll start a new thread about it.
>
> I hope you can try and see if it works for bash-ts-mode, when you have
> time. You should only need to apply the attached patch and (goto-char
> (treesit--navigate-defun (point) …)) should just work. You can switch
> between top-level/nested with treesit-defun-tactic.
>

Cool. Thanks for all the work. I will test it and report my experience in
the other thread.


>
> Anyway, here is some minor points of the patch:
>
> +;;; Tree-sitter navigation
> +
> +(defun sh-mode--treesit-defun-p (node)
> +  "Return t if NODE is a function and nil otherwise."
> +  (string-match treesit-defun-type-regexp
> +                (treesit-node-type node)))
> +
> +(defun sh-mode-treesit-not-cs-p (node)
> +  "Return t if NODE is *not* a compound-statement and nil otherwise."
> +  (lambda (p)
> +    (not (string-match "compound_statement"
> +                       (treesit-node-type p)))))
>
> We probably want this to be an internal function, too, right?
>

I agree. Those are generic enough to be useful to other use cases.

+(defmacro sh-mode--treesit-parent-defun (node)
> +  "Return nearest function-node that surrounds NODE, if any, or nil.
> +
> +This macro can be used to determine if NODE is within a function.  If
> +so, the macro evaluates to the nearest function-node and parent of NODE.
> +Otherwise it evaluates to NIL."
> +  `(treesit-parent-until ,node 'sh-mode--treesit-defun-p))
> +
> +(defmacro sh-mode--treesit-oldest-parent-in-defun (node)
> +  "Return oldest parent of NODE in common function, if any, or NIL.
> +
> +This function returns the oldest parent of NODE such that the common
> +parent is the nearest function-node."
> +  `(treesit-parent-while ,node 'sh-mode--treesit-not-cp-p))
>
> I'd prefer we use functions when functions will do, unless you have
> particular reasons to use macros (for performance?).


Yes, I was thinking about performance but out of intuition and not evidence.


> Diff artifact?
>

Yes, my bad.

Looks good to me, but I didn't scrutinize it line-by-line. If the new
> system works well, bash-ts-mode (and other major modes) wouldn't need to
> implemente its own navigation function. Sorry for not end up using your
> hard work, but your work definitely helped me to implement the more general
> version of defun navigation!
>

No problem at all. Trying things out has been a great opportunity for me to
learn. Thank you for taking the time to review my patch.

Regarding the new navigation functions the do work as documented for
bash-ts-mode. However, the overall behavior feels awkward to me. I will
elaborate on the new thread.

-- 
João Paulo L. de Carvalho
Ph.D Computer Science |  IC-UNICAMP | Campinas , SP - Brazil
Postdoctoral Research Fellow | University of Alberta | Edmonton, AB - Canada
joao.carvalho@ic.unicamp.br
joao.carvalho@ualberta.ca

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