From: Stefan Monnier <monnier@iro.umontreal.ca>
To: phillip.lord@newcastle.ac.uk (Phillip Lord)
Cc: Emacs-Devel devel <emacs-devel@gnu.org>
Subject: Re: disabling undo boundaries
Date: Mon, 11 May 2015 10:45:49 -0400 [thread overview]
Message-ID: <jwv4mnj2nxm.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <87617zl4kh.fsf@newcastle.ac.uk> (Phillip Lord's message of "Mon, 11 May 2015 12:46:38 +0100")
> The problem seems to come from here in record_point, in undo.c
> if ((current_buffer != last_undo_buffer)
> /* Don't call Fundo_boundary for the first change. Otherwise we
> risk overwriting last_boundary_position in Fundo_boundary with
> PT of the current buffer and as a consequence not insert an
> undo boundary because last_boundary_position will equal pt in
> the test at the end of the present function (Bug#731). */
> && (MODIFF > SAVE_MODIFF))
> Fundo_boundary ();
> last_undo_buffer = current_buffer;
Oh, I think you're right, this is even more likely the reason for
those boundaries.
> The best thing that I can think of at the moment is to use
> post-command-hook to clean up the excessive undo-boundaries, but I am
> not sure how I am going to work out which ones are "real" and which ones
> not. The obvious solution (delete all those adding since the last
> command) will fail for both self-insert-command's logic and anywhere
> else that undo-boundary has been explicitly called.
Indeed, removing those boundaries after the fact seems
difficult/tricky/risky.
I'm not sure exactly what are your design constraints, but I can see
a few alternatives:
- disable undo in the "other buffer" (*scratch* in your example, tho
I suspect it's a different buffer in your real case).
- delay the modification of the other buffer (e.g. record in a-c-f the
boundaries of the affected text, and process them later from
post-command-hook). Not sure if this would really help.
- change your a-c-f so it records the buffer-undo-list at the beginning,
and it removes the added boundary (if any) at the end.
Stefan
next prev parent reply other threads:[~2015-05-11 14:45 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-10 21:43 disabling undo boundaries Phillip Lord
2015-05-11 1:42 ` Stefan Monnier
2015-05-11 11:46 ` Phillip Lord
2015-05-11 14:45 ` Stefan Monnier [this message]
2015-05-11 16:31 ` Phillip Lord
2015-05-11 19:30 ` Stefan Monnier
2015-05-11 20:42 ` Phillip Lord
2015-05-11 22:23 ` Stefan Monnier
2015-05-12 11:52 ` Phillip Lord
2015-05-12 20:15 ` Stefan Monnier
2015-05-12 20:59 ` Phillip Lord
2015-05-13 12:32 ` Stefan Monnier
2015-05-13 15:40 ` Phillip Lord
2015-05-14 15:28 ` Stefan Monnier
2015-05-15 12:27 ` Phillip Lord
2015-05-15 18:08 ` Stefan Monnier
2015-05-15 19:49 ` Phillip Lord
2015-05-15 23:45 ` Stefan Monnier
2015-05-16 13:31 ` Phillip Lord
2015-05-19 11:59 ` Phillip Lord
2015-05-19 19:42 ` Stefan Monnier
2015-05-19 21:48 ` Phillip Lord
2015-05-20 2:00 ` Stefan Monnier
2015-05-20 7:45 ` Phillip Lord
2015-05-20 12:53 ` Stefan Monnier
2015-05-21 11:15 ` Phillip Lord
2015-05-21 15:44 ` Stefan Monnier
2015-05-21 17:03 ` Phillip Lord
2015-05-27 11:46 ` Phillip Lord
2015-06-29 0:46 ` Stefan Monnier
2015-08-04 14:18 ` Phillip Lord
2015-08-06 21:02 ` Phillip Lord
2015-08-06 22:20 ` Stefan Monnier
2015-08-07 13:40 ` Phillip Lord
2015-08-07 13:59 ` David Kastrup
2015-08-07 21:10 ` Phillip Lord
2015-08-08 5:39 ` David Kastrup
2015-08-08 9:58 ` Phillip Lord
2015-08-07 17:10 ` Stefan Monnier
2015-08-08 21:28 ` Stefan Monnier
2015-08-09 15:39 ` Phillip Lord
2015-08-09 16:30 ` Stefan Monnier
2015-08-09 16:50 ` Phillip Lord
2015-08-09 17:40 ` Stefan Monnier
2015-08-10 9:27 ` Phillip Lord
2015-08-10 21:21 ` Phillip Lord
2015-08-12 21:15 ` Stefan Monnier
2015-08-12 22:34 ` Phillip Lord
2015-08-13 2:23 ` Stefan Monnier
2015-08-21 9:40 ` Phillip Lord
2015-08-07 23:49 ` Davis Herring
2015-08-08 10:01 ` Phillip Lord
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