Re: Debouncing slow mode line constructs (was: Emacs design and architecture. How about copy-on-write?)

[Eli Zaretskii]

> From: Ihor Radchenko <yantar92@posteo.net>
> Cc: Po Lu <luangruo@yahoo.com>, Eli Zaretskii <eliz@gnu.org>, acm@muc.de,
>  incal@dataswamp.org, emacs-devel@gnu.org
> Date: Thu, 21 Sep 2023 11:36:34 +0000
> 
> What about automatically debouncing slow :eval constructs in the mode
> line? If we make sure that :eval constructs running longer than a
> threshold do not run too frequently, it can certainly improve user
> experience.

How do you propose to evaluate just portions of the mode line?  What
will the :eval whose processing is bypassed yield, and how will that
affect processing of the rest of mode-line-format, given its
highly-recursive processing structure and the fact that the text
produced by this processing is laid out as it is produced?