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From: Michael Heerdegen <michael_heerdegen@web.de>
To: help-gnu-emacs@gnu.org
Subject: Re: How to temporarily show an image in an Emacs buffer?
Date: Wed, 08 Mar 2023 17:41:23 +0100	[thread overview]
Message-ID: <87sfefi4b0.fsf@web.de> (raw)
In-Reply-To: 87a60nerz2.fsf@mbork.pl

Marcin Borkowski <mbork@mbork.pl> writes:

> On 2023-03-08, at 05:53, Marcin Borkowski <mbork@mbork.pl> wrote:
>
> > Alternatively, it _may_ change the buffer contents but in a way that is
> > not recorded in `buffer-undo-list'.  Is that possible?
>
> I did some experimenting, and this
>
> (defvar no-undo-marker (make-marker))
> (defun no-undo-insert ()
>   "Test undo."
>   (save-excursion
>     (let ((buffer-undo-list))
>       (set-marker no-undo-marker (point))
>       (insert "this can't be undone\n"))))
> [...]

Regardless of what has already been said, just for the sake of
completeness: AFAIK the intended way to inhibit the recording of undo
is to bind buffer-undo-list to t (not to nil).

There are lots of use case in the sources - see e.g.
`image-toggle-display-text'.

Michael.




  parent reply	other threads:[~2023-03-08 16:41 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-08  4:53 How to temporarily show an image in an Emacs buffer? Marcin Borkowski
2023-03-08  5:23 ` Marcin Borkowski
2023-03-08  6:19   ` Ruijie Yu via Users list for the GNU Emacs text editor
2023-03-08 16:01     ` Marcin Borkowski
2023-03-08 16:41   ` Michael Heerdegen [this message]
2023-03-11  8:14     ` Marcin Borkowski
2023-03-12  3:37       ` Michael Heerdegen
2023-03-12  7:46         ` Marcin Borkowski
2023-03-08 13:38 ` Eli Zaretskii
2023-03-08 16:00   ` Marcin Borkowski
2023-03-13  8:29     ` Jean Louis
2023-03-13  9:27       ` Marcin Borkowski
2023-04-01 15:57       ` Marcin Borkowski
2023-03-10 16:26 ` Stefan Monnier via Users list for the GNU Emacs text editor
2023-03-11  8:15   ` Marcin Borkowski

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