From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: "after" variable watchers Date: Tue, 18 May 2021 11:57:38 -0400 Message-ID: References: <83lf8du09t.fsf@gnu.org> <3431d752-559a-7d33-e2fb-2d81dd6cc794@gmx.at> <5a8b6fc9-cca8-374c-39f8-3f3d0f83fbca@gmx.at> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="4280"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cc: Eli Zaretskii , npostavs@gmail.com, emacs-devel@gnu.org To: martin rudalics Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue May 18 18:12:28 2021 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 1lj2KY-0000t9-UV for ged-emacs-devel@m.gmane-mx.org; Tue, 18 May 2021 18:12:27 +0200 Original-Received: from localhost ([::1]:52402 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lj2KX-00057S-SP for ged-emacs-devel@m.gmane-mx.org; Tue, 18 May 2021 12:12:25 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:44332) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lj26Q-0002Y5-1a for emacs-devel@gnu.org; Tue, 18 May 2021 11:57:51 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:16171) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lj26I-0006ak-J6; Tue, 18 May 2021 11:57:47 -0400 Original-Received: from pmg2.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id DECE1806A5; Tue, 18 May 2021 11:57:40 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 837EE804FD; Tue, 18 May 2021 11:57:39 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1621353459; bh=+h1NwbXz4jl+vrf38zsGcDucDhCXptybAp1VddOtGZU=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=QG8ob+9tud1hZmzsZ/Z0GR3JDmMoBKF8vTQc3PjLVjqcrTWAIxCbwn2hda4lAX+Zg al/9sXI//Cf3moB+Axt9dgZIg0ztSbVVq+pfg+SvRqBmxsiIS91ZxjFzb0ryE3U5JR uFSpO8kr///r2qzuJmdXYud09OO1sMrjIA4Rv/3B12iBYdTabFBOulJ28B0S5HpgvS AvGCxOiIFP5H0jVGDQOjVpDzKDo0xhJcaDZy6UyVba2HyuYpJjpmBIEtBZ+ff/uCjv J3djA0GyjHNX/kimAJqyWyiJ9iXCPdjfYzlyUvTMaMmEACv8oxrkt3n3AEW3tfqqGN e5e18ZXf5mjzw== Original-Received: from alfajor (76-10-140-76.dsl.teksavvy.com [76.10.140.76]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 50F6512001E; Tue, 18 May 2021 11:57:39 -0400 (EDT) In-Reply-To: <5a8b6fc9-cca8-374c-39f8-3f3d0f83fbca@gmx.at> (martin rudalics's message of "Tue, 18 May 2021 17:10:47 +0200") Received-SPF: pass client-ip=132.204.25.50; envelope-from=monnier@iro.umontreal.ca; helo=mailscanner.iro.umontreal.ca X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 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" Xref: news.gmane.io gmane.emacs.devel:269466 Archived-At: martin rudalics [2021-05-18 17:10:47] wrote: >>> window_updeco_window is called indirectly from all places that change a >>> window's decorations, font or size. >> >> Would it make sense to call it more lazily, e.g. as part of redisplay >> (basically, the watchpoints would just set some dirty bits and then at >> the beginning of redisplay you'd then run `window_updeco_window` on >> those windows with the dirty bit set)? > > That was my first approach given our current implementation of watch > points. I spent a couple of weeks on it but it didn't really work out. > Between the time a variable is set and the time the setting is applied, > the "realized" values would be inaccurate. These values are, however, > needed in too many places before we start redisplaying a window. What was the problem you encountered when you tried to add: if () window_updeco_window (...); to the getters of the realized values? > I do not want to exclude that such a lazy approach could work. But it > would require more profound changes to the way window sizes and > decorations are processed than the approach based on "after" variable > watchers. You obviously know more about this code, so I can't say much more. I was just pointing in the direction of using dirty "bits" (it's actually often better to represent dirty state via things like our buffer ticks than via actual `dirty` bits) because it's the standard solution for such problems: experience has usually shown that decoupling the setting of vars from the execution of the consequences usually leads to a much more solid design where it's much easier to deal with problems of inf-loops or (in)efficiency. Stefan