On Sat, Dec 3, 2022 at 2:46 PM Alan Mackenzie <acm@muc.de> wrote:

> Yes.  beginning-of-defun and end-of-defun are broken, and have been for
> a long time.  They cannot, in general, work, for the reason you've just
> noted.
>

Thanks for confirming this, Alan. For a moment I thought that I was making
one of those elisp newbie mistakes.


> The problem has been raised on emacs-devel before, without the problem
> getting solved.  CC Mode, for example, works around the problem by
> binding c-beginning-of-defun and c-end-of-defun directly to C-M-a and
> C-M-e, bypassing the offending code.
>

I think for now I will use the same workaround.


> The tactic of using beginning-of-defun-raw is only valid in certain
> circumstances, and is an inappropriate inefficiency in modes such as
> the one you're writing, where it is just as easy to go directly to an
> end of defun as a beginning of defun.
>
> > What I think is happening is that, when `end-of-defun' calls
> > `beginning-of-defun-raw' it brings point to the beginning of a top-level
> > function, so the subsequent call to `end-of-defun' moves point to the
> start
> > location, does it make it seems as the point did not move.
>
> Yes.  I suggest you submit a bug report for this bug.
>

I will put some time into this and see if I can come up with a patch before
flagging it as a bug.


> To work properly, beginning/end-of-defun need to know whether the
> starting point is inside a defun or between defuns.  Your patch includes
> a macro which determines this (as CC Mode includes a function which
> determines this).  Possibly, a proper bug fix might include a function
> supplied by the major mode for this analysis.
>

Indeed. I am not sure if that would be as easy as without tree-sitter, but
such a function is definitely handy and easy to implement thanks to Yuan's
efforts to bring tree-sitter to core.

-- 
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