Re: Use (eval-when-compile 'treesit) to save us from writing declare-function forms

[Yuan Fu <casouri@gmail.com>]

> On Dec 4, 2024, at 10:57 AM, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> From: Yuan Fu <casouri@gmail.com>
>> Date: Wed, 4 Dec 2024 10:19:42 -0800
>> Cc: emacs-devel@gnu.org
>> 
>> 
>> 
>>> On Dec 3, 2024, at 5:12 AM, Eli Zaretskii <eliz@gnu.org> wrote:
>>> 
>>> I don't understand" c-ts-mode.el already does
>>> 
>>> (require 'treesit)
>>> 
>>> So what would eval-when-compile add to that?
>> 
>> When Emacs is built without tree-sitter, none of the treesit.c functions are available (except for treesit-ready-p). Now if this Emacs compiles c-ts-mode.el, it’ll signal undefined function error for all those functions. So we add declare-function forms for all the treesit.c functions used in c-ts-mode.el, and have to update the declare-function forms whenever we use some new treesit.c functions.
>> 
>> If we use eval-when-compile, we don’t need to write declare-function forms in c-ts-mode.el anymore, because treesit.el has declare-function forms for all treesit.c functions.
> 
> That's what I don't understand: how will eval-when-compile which loads
> treesit.el be different from (require 'treesit) we already have in
> c-ts-mode?  Don't they both load treesit.el?

I maybe wrong here, but I thought if you don’t use eval-when-compile, simply byte-compiling c-ts-mode.el wouldn’t load treesit.el?

Yuan