Re: Concurrency via isolated process/thread

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Cc: yantar92@posteo.net,  emacs-devel@gnu.org
> Date: Sun, 09 Jul 2023 15:14:36 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > What's more, I don't think anyone really wants to have to
> > write Lisp programs in a completely different way when we want them to
> > run from threads.
> 
> When programmers write such code for other interactive programs, they
> are comfortable with the limitations of running code outside of the UI
> thread.  Why should writing new, thread-safe Lisp for Emacs be any more
> difficult?

Because we'd need to throw away 40 years of Lisp programming, and
rewrite almost every bit of what was written since then.  It's a huge
setback for writing Emacs applications.

> > Those mechanisms only work when Emacs is idle, which is bad for
> > features like progress reporting.  Doing this right requires to
> > redesign how redisplay kicks in, and probably have several different
> > kinds of redisplay, not one.
> 
> Maybe.  I haven't worked out the details of that yet, but in most other
> GUI programs and toolkits, messages from other threads can only be
> processed by the UI thread while it is idle.

Emacs doesn't have a UI thread, as you know.