bug#64442: 29.0.92; treesit-beginning-of-defun fails in DEFUN functions in C

[Yuan Fu]

> On Aug 10, 2023, at 2:18 AM, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> Cc: 64442@debbugs.gnu.org
>> Date: Sun, 30 Jul 2023 10:10:35 +0300
>> From: Eli Zaretskii <eliz@gnu.org>
>> 
>>> From: Yuan Fu <casouri@gmail.com>
>>> Date: Tue, 11 Jul 2023 19:10:01 -0700
>>> Cc: 64442@debbugs.gnu.org
>>> 
>>> 
>>> 
>>>> On Jul 6, 2023, at 11:40 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>>>> 
>>>>> From: Yuan Fu <casouri@gmail.com>
>>>>> Date: Thu, 6 Jul 2023 23:15:00 -0700
>>>>> Cc: 64442@debbugs.gnu.org
>>>>> 
>>>>>> On Jul 4, 2023, at 4:39 AM, Eli Zaretskii <eliz@gnu.org> wrote:
>>>>>> 
>>>>>> Why cannot we look for a top-level expression_statement node which is
>>>>>> a call_expression whose function identifier is "DEFUN" and whose
>>>>>> position is between the place where C-M-a was invoked and the place
>>>>>> where it does find a defun?
>>>>> 
>>>>> It’s gonna be ugly, but I can take a jab at it this weekend. I’m thinking 
>>>>> of a wrapper function that tries to detect DEFUN before falling back to 
>>>>> the ordinary tree-sitter defun movement function.
>>>> 
>>>> Thanks.  let's see how ugly it is before deciding whether it's worth it.
>>>> 
>>>>>> DEFUN's cannot be nested, so we don't need to consider that.
>>>>> 
>>>>> Yeah, in general C sources don’t have nested defuns, only C++ ones do.
>>>> 
>>>> No, I meant the use of DEFUN macros in Emacs cannot be nested.
>>> 
>>> Just an update. I didn’t forget about this, but it’s more harder than I 
>>> thought and I’m still working on it :-(
>> 
>> Any progress with this?  It would be good to have a solution in Emacs
>> 29.2, if possible.
> 
> Ping!

I still don’t have a good solution. But I just realized that we might be able 
to make a little compromise: what if Emacs recognizes DEFUN, but as two 
separate parts (the declaration and the body), rather than one? It’s hard to 
make it recognize DEFUN as a single defun, but making it recognize DEFUN as two 
parts is easy.

Try this patch and see if you like the behavior. Personally I find it quite 
alright.

Yuan

defun-nav.patch
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