bug#61208: 29.0.60; treesit-beginning/end-of-defun problem with macros in c-ts-mode

[Yang Yingchao via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

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On Thu, Feb 02 2023, Yang Yingchao <yang.yingchao@qq.com> wrote:

> On Wed, Feb 01 2023, Theodor Thornhill <theo@thornhill.no> wrote:
>
>> Eli Zaretskii <eliz@gnu.org> writes:
>>
>>>> Cc: yang.yingchao@qq.com
>>>> Date: Wed, 01 Feb 2023 14:33:24 +0800
>>>> From:  Yang Yingchao via "Bug reports for GNU Emacs,
>>>>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
>>>>
>>>>
>>>> #define SWITCH()
>>>> #define CASE(name)		case name:
>>>>
>>>> void func(int i)        // LINE_E
>>>> {
>>>>     SWITCH(i)           // LINE_D
>>>>     {
>>>>         CASE(A)         // LINE_C
>>>>         {
>>>>             ;
>>>>         }
>>>>         CASE(B)         // LINE_B
>>>>         {
>>>>             ;           // LINE_A
>>>>         }
>>>>     }
>>>> }
>>>>
>>>> When cursor is at LINE_A, and stoke `C-M-a`, cursor will go to LINE_B;
>>>> then `C-M-a` again, cursor goes to LINE_C, then `C-M-a` again, LINE_D,
>>>> and `C-M-a` again, finally to LINE_E...
>>>
>>> Set treesit-defun-tactic to 'top-level, and your problem is solved.
>>>
>>> Yuan, Theo: do we want to have that set by default in ts-c-mode?  C
>>> doesn't have nested functions, so it should be a better default, what
>>> with all the cpp madness that the C grammar doesn't grok.
>>>
>>> Maybe also in C++ and Java -- AFAIU they don't have nested functions
>>> either.
>>>
>>> WDYT?
>>
>> I'm fine with that change, I think.  Other, "smaller" constructs can be
>> found as sentences or sexps anyway, I think.
>>
>> Theo
>

Thanks for the help.

But in the following C++ code, is it possible to make treesit-beginning/end-of-defun behaves the same as c++-mode ?

,----
| class Test       // LINE_D
| {
| public:
|     Test(int i)  // LINE_C
|     {
|         SWITCH(i)
|         {
|             CASE(A)
|             {
|                 ;
|             }
|             CASE(B) // LINE_B
|             {
|                 ; // LINE_A
|             }
|         }
|     }
| };
`----

When cursor is at LINE_A, if in c++-mode, `C-M-a` moves cursor to LINE_C, which is correct.
But in c++-ts-mode, behaviour of  `C-M-a` is wrong:
if treesit-defun-tactic is nested, it moves to line_B, and if treesit-defun-tactic is top-level,
it moves to LINE_D. Both of them are actually wrong...


--
Yang Yingchao
Yang Yingchao