Re: Redisplay hook

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Clément Pit--Claudel <clement.pit@gmail.com>,
>   emacs-devel@gnu.org
> Date: Mon, 04 Jul 2016 03:55:05 -0400
> 
> I don't have a clear recollection either, sorry.

It happens ;-)

> I guess part of the question is what would be the use of such a hook.
> The difference between a pre-redisplay-hook and a
> post-redisplay-hook is not very large since most of the result of
> redisplay is "invisible" to Elisp.  The main differences I can think of
> would be:
> - jit-lock stuff, in case you want to see the buffer after jit-locking.
>   but it seems you can just as well hook into jit-lock to get
>   that result.
> - scrolling, in case you want to react to changes in the user-visible
>   window-start/end.

The use case which started this thread is yet another use case which
definitely wants to run after a frame was updated.

> Of course the use could be fairly tricky, with risks of the
> post-redisplay-hook causing further redisplay-cycle ad-nauseam, but we
> already have this problem with the window-scroll-functions, IIRC.

Yes, getting this solved should be part of the job.

Thanks.