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: bug-reference-prog-mode slows down CC Mode's scrolling by ~7% Date: Fri, 3 Sep 2021 16:52:55 +0000 Message-ID: References: <83a6kuyysv.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="26698"; mail-complaints-to="usenet@ciao.gmane.io" Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Fri Sep 03 18:53:42 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 1mMCRi-0006j6-Cd for ged-emacs-devel@m.gmane-mx.org; Fri, 03 Sep 2021 18:53:42 +0200 Original-Received: from localhost ([::1]:56688 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mMCRg-0003BX-Eu for ged-emacs-devel@m.gmane-mx.org; Fri, 03 Sep 2021 12:53:40 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:41882) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mMCR2-0002WB-Ui for emacs-devel@gnu.org; Fri, 03 Sep 2021 12:53:00 -0400 Original-Received: from colin.muc.de ([193.149.48.1]:41461 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.90_1) (envelope-from ) id 1mMCR0-0006Nl-L8 for emacs-devel@gnu.org; Fri, 03 Sep 2021 12:53:00 -0400 Original-Received: (qmail 30027 invoked by uid 3782); 3 Sep 2021 16:52:55 -0000 Original-Received: from acm.muc.de (p4fe1598b.dip0.t-ipconnect.de [79.225.89.139]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Fri, 03 Sep 2021 18:52:55 +0200 Original-Received: (qmail 6538 invoked by uid 1000); 3 Sep 2021 16:52:55 -0000 Content-Disposition: inline In-Reply-To: <83a6kuyysv.fsf@gnu.org> X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de Received-SPF: pass client-ip=193.149.48.1; 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_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:273808 Archived-At: Hello, Eli. On Fri, Sep 03, 2021 at 09:10:24 +0300, Eli Zaretskii wrote: > > Date: Thu, 2 Sep 2021 19:24:51 +0000 > > From: Alan Mackenzie > > Cc: emacs-devel@gnu.org > > In words (;-), only the first function on jit-lock-functions should > > be able to expand the region which gets `fontified' text properties. > > This expanded region will then be supplied to the subsequent > > functions. > > Given how little used the `jit-lock-bounds' mechanism is (there is > > one function in Emacs, font-lock-default-fontify-region, which uses > > it, and a web search revealed only a single other instance, in > > lsp-mode on git-hub), this shouldn't cause problems. In fact, I'm > > not sure the lsp-mode use of it is even correct. > Bother: this is not future-proof, and certainly isn't scalable. If we > are changing the protocol, can we instead come up with a more scalable > change, so that functions won't "fight" in the future who gets to be > "the first"? OK, so the problem is how do we cope with two (or even several) "first" functions? How about something like this: o - We still have a first function, font-lock-fontify-region. o - We call the next function with the jit-lock-bounds returned by the previous one. Repeat this step with steadily expanding bounds for each function in jit-lock-functions. o - if (< BEG-final BEG-1) we go through jit-lock-functions again on the region (BEG-final BEG-1). Do the same for END-final. During this stage, we ignore the returned jit-lock-bounds. o - We set the `fontified' text properties on the region (BEG-final END-final). This needn't actually be too complicated. The current jit-lock--run-functions already calculates BEG-final and END-final (it calls them loose-beg and loose-end). For this mechanism, it would still be best to have all the functions using jit-lock-bounds together at the start of jit-lock-functions, though this would be an optimsation rather than essential to the functionality. -- Alan Mackenzie (Nuremberg, Germany).