From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Marcin Borkowski Newsgroups: gmane.emacs.help Subject: Re: How to temporarily show an image in an Emacs buffer? Date: Sat, 11 Mar 2023 09:14:07 +0100 Message-ID: <87fsabogc0.fsf@mbork.pl> References: <87bkl3etd1.fsf@mbork.pl> <87a60nerz2.fsf@mbork.pl> <87sfefi4b0.fsf@web.de> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="31482"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: mu4e 1.1.0; emacs 30.0.50 Cc: help-gnu-emacs@gnu.org To: Michael Heerdegen Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sat Mar 11 09:14:52 2023 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pauNQ-0007x6-Be for geh-help-gnu-emacs@m.gmane-mx.org; Sat, 11 Mar 2023 09:14:52 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pauMu-00035U-PF; Sat, 11 Mar 2023 03:14:20 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pauMt-00035K-Bo for help-gnu-emacs@gnu.org; Sat, 11 Mar 2023 03:14:19 -0500 Original-Received: from mail.mojserwer.eu ([195.110.48.8]) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pauMr-00083k-HD for help-gnu-emacs@gnu.org; Sat, 11 Mar 2023 03:14:19 -0500 Original-Received: from localhost (localhost [127.0.0.1]) by mail.mojserwer.eu (Postfix) with ESMTP id 9D520227158A; Sat, 11 Mar 2023 09:14:13 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at mail.mojserwer.eu Original-Received: from mail.mojserwer.eu ([127.0.0.1]) by localhost (mail.mojserwer.eu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id bUKVhB5H47-z; Sat, 11 Mar 2023 09:14:10 +0100 (CET) Original-Received: from localhost (178235147152.dynamic-3-poz-k-0-1-0.vectranet.pl [178.235.147.152]) by mail.mojserwer.eu (Postfix) with ESMTPSA id 75A972271589; Sat, 11 Mar 2023 09:14:10 +0100 (CET) In-reply-to: <87sfefi4b0.fsf@web.de> Received-SPF: pass client-ip=195.110.48.8; envelope-from=mbork@mbork.pl; helo=mail.mojserwer.eu X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.help:142982 Archived-At: On 2023-03-08, at 17:41, Michael Heerdegen wrote: > Marcin Borkowski writes: > >> On 2023-03-08, at 05:53, Marcin Borkowski 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). Thanks, I missed that. > There are lots of use case in the sources - see e.g. > `image-toggle-display-text'. I didn't experiment with this, but I'm afraid that interlacing changes to the buffer done by the user (when recording undo changes) and by the Elisp code (while `buffer-undo-list' is bound to `t') may result in undoing being impossible. Anyway, I solved /my/ particular problem using overlays. Thanks! -- Marcin Borkowski http://mbork.pl