Re: Gap buffer problem?

[Gerd Möllmann]

Pip Cet <pipcet@protonmail.com> writes:

> "Eli Zaretskii" <eliz@gnu.org> writes:
>
>>> From: Gerd Möllmann <gerd.moellmann@gmail.com>
>>> Cc: "Pip Cet via \"Emacs development discussions.\"" <emacs-devel@gnu.org>,
>>>  Óscar Fuentes <ofv@wanadoo.es>
>>> Date: Wed, 11 Dec 2024 16:33:18 +0100
>>>
>>> Pip Cet <pipcet@protonmail.com> writes:
>>>
>>> > This may be a very stupid idea, but why not use a separate process?
>>>
>>> Not stupid at all. I thought about something similar in a different
>>> context, namely if one could decouple the GUI part of Emacs from the
>>> rest.
>>
>> If it can be done by two processes, it can also be done by two threads
>> in the same process.  Right?
>
> AFAIU: No, not right.
>
> I may have misunderstood, but if the idea is to preserve a consistent
> state of all Lisp data and buffer text for redisplay to use, the easiest
> way to ensure that consistency is fork().  The other ways, such as
> copying all heap objects that might be used by redisplay (and adjusting
> all internal pointers in such heap objects to point to the copy rather
> than the original data), probably will end up either being a lot slower
> or being very specific to the system we're running on.

I may also be misunderstanding, but in principle, I agree with Eli.

Say we have processes A and B communicating with each other. Take the
code of A and move it to B, possibly with some automatic transformations
if A and B have the same source code. Make two threads in the result
process for A and B. Replace inter-process message passing with
inter-thread message passing. Initial message may be "fork" transferring
the world of thread A to thread B.

But I'm also thinking too abstract sometimes.