From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: Making Emacs Lisp easier to debug Date: Sat, 11 Nov 2023 14:56:17 +0000 Message-ID: References: <838r74ye77.fsf@gnu.org> <83fs1cwnnv.fsf@gnu.org> <83edgwwge0.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="35942"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Nov 11 15:56:55 2023 Return-path: Envelope-to: ged-emacs-devel@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 1r1pPr-00098Y-9u for ged-emacs-devel@m.gmane-mx.org; Sat, 11 Nov 2023 15:56:55 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1r1pPO-0004CU-7R; Sat, 11 Nov 2023 09:56:26 -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 1r1pPL-0004CL-6j for emacs-devel@gnu.org; Sat, 11 Nov 2023 09:56:23 -0500 Original-Received: from mail.muc.de ([193.149.48.3]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r1pPJ-0003y7-8l for emacs-devel@gnu.org; Sat, 11 Nov 2023 09:56:22 -0500 Original-Received: (qmail 49655 invoked by uid 3782); 11 Nov 2023 15:56:18 +0100 Original-Received: from acm.muc.de (p4fe151aa.dip0.t-ipconnect.de [79.225.81.170]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Sat, 11 Nov 2023 15:56:18 +0100 Original-Received: (qmail 5280 invoked by uid 1000); 11 Nov 2023 14:56:18 -0000 Content-Disposition: inline In-Reply-To: <83edgwwge0.fsf@gnu.org> X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de Received-SPF: pass client-ip=193.149.48.3; envelope-from=acm@muc.de; helo=mail.muc.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:312582 Archived-At: Hello, Eli. On Sat, Nov 11, 2023 at 15:47:51 +0200, Eli Zaretskii wrote: > > Date: Sat, 11 Nov 2023 12:10:33 +0000 > > Cc: emacs-devel@gnu.org > > From: Alan Mackenzie > > > (I also don't understand why you think this will help with font-lock, > > > nor even how it would work in general, should it be possible. > > With font lock, or any other Lisp hook called from redisplay, it should > > be possible, in a recursive-edit loop, to run edebug, displaying on a > > different frame. That different frame would be running in the inner > > redisplay while the outer redisplay would be suspended. > Why do you need an inner redisplay for that? Because the outer redisplay would be the thing being debugged, and hence not in a position to display the progress of edebug. > And what will that frame show, given that the outer redisplay is > halfway through fontifying the text? what do you expect to see there, > and why? I think the scope of a redisplay operation could change from everything to a single frame. So in normal operation a high level routine would call redisplay2 for each of Emacs's frames in turn. While stepping through a hook in edebug in the inner redisplay, the outer redisplay would (I think) carry on looking like it did before the outer redisplay started. Or, possibly, it might look like a bare frame, I'm not sure. > > > Re-entering redisplay in the middle of a redisplay cycle means that > > > the outer redisplay didn't finish preparing the glyph matrices, and > > > what do you want the inner redisplay to do in such a case? > > Work with the glyph matrices belonging to the inner redisplay whilst the > > outer one is suspended. > But that will immediately get you into the same problem, since the > offending window will get redisplayed by the inner redisplay, and will > again cause Edebug, etc., ad nauseam. We could put a limit on the nesting depth of redisplay nesting that edebug would cope with, a small integer (2 or 3, probably). That is very similar to what edebug currently does during a redisplay, i.e. it bypasses edebug's processing entirely. > > As I say, it is not clear whether or not this is possible or > > practicable. If it were, we could enhance edebug such that a function > > in a font lock pattern, or on, say, window-scroll-functions could be > > edebugged by doing nothing more than instrumenting it with C-u C-M-x. > > Thus Lisp called from redisplay would cease to be an awkward special > > case as far as debugging is concerned. > I think we should start by having a clear idea of what should such an > "inner redisplay" show and how, before we are talking about > implementing it. I agree. > My impression from what you wrote is that the idea is way too vague to > discuss the details, .... Yes. It's currently just a vague idea, and it's not even clear as yet whether it's practicable. But if it is, I think it would be worthwhile implementing. > .... and what you call "inner redisplay" is not what you want at all. I don't understand why you say this. Do you see any particular problems with it (in addition to what you've already written), or perhaps have a better scheme for running edebug on redisplay's several Lisp hooks? -- Alan Mackenzie (Nuremberg, Germany).