Re: save-excursion and multi-thread?

[Richard Stallman]

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  > IIUC what you mean by "keep ... point alone", this already happens.
  > (But not for mark: for that, you need save-mark-and-excursion
  > nowadays.)  That is, when the save-excursion form is exited, point is
  > guaranteed to be where it was when we entered save-excursion.

That's half of it.  The other half of what I had in mind is that
changes in point, in other threads, should not affect point inside the
save-excursion form in this thread.

  > Note that this might expose background point movements to the user,
  > depending on which thread runs redisplay.

I see what you are getting at -- but I think it would be good to
make this controllable.

One idea: perhaps there should be a way to control which thread's
context redisplay should occur in.  Perhaps on a per-window basis.

Perhaps each window should be "owned" by a thread, so that point for
that window will be displayed wherever that thread puts it.  If we can
make this happen by default in a way that is usually right, it might
not take much additional work.  Perhaps the default should be
whichever thread last operated on it, in some sense.

-- 
Dr Richard Stallman (https://stallman.org)
Chief GNUisance of the GNU Project (https://gnu.org)
Founder, Free Software Foundation (https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)