From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: [Emacs-diffs] emacs-24 d69e9f1: CC Mode: Stop Font Lock forcing fontification from BOL. Fixes debbugs#19669. Date: Fri, 20 Mar 2015 16:30:28 +0000 Message-ID: <20150320163027.GB3493@acm.fritz.box> References: <20150201212213.17840.3710@vcs.savannah.gnu.org> <55076CF8.60309@dancol.org> <20150318120806.GA4160@acm.fritz.box> <550A43BB.3070904@dancol.org> <20150319093110.GA2753@acm.fritz.box> <20150319203724.GB2753@acm.fritz.box> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1426869082 11289 80.91.229.3 (20 Mar 2015 16:31:22 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 20 Mar 2015 16:31:22 +0000 (UTC) Cc: Daniel Colascione , emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Mar 20 17:31:11 2015 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1YYzpD-0003bA-2v for ged-emacs-devel@m.gmane.org; Fri, 20 Mar 2015 17:31:07 +0100 Original-Received: from localhost ([::1]:44749 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YYzpC-0001cS-6o for ged-emacs-devel@m.gmane.org; Fri, 20 Mar 2015 12:31:06 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:42561) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YYzp1-0001Gq-Iu for emacs-devel@gnu.org; Fri, 20 Mar 2015 12:31:01 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YYzow-00074N-JW for emacs-devel@gnu.org; Fri, 20 Mar 2015 12:30:55 -0400 Original-Received: from colin.muc.de ([193.149.48.1]:51733 helo=mail.muc.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YYzow-000740-Aa for emacs-devel@gnu.org; Fri, 20 Mar 2015 12:30:50 -0400 Original-Received: (qmail 52710 invoked by uid 3782); 20 Mar 2015 16:30:47 -0000 Original-Received: from acm.muc.de (pD951ACB9.dip0.t-ipconnect.de [217.81.172.185]) by colin.muc.de (tmda-ofmipd) with ESMTP; Fri, 20 Mar 2015 17:30:46 +0100 Original-Received: (qmail 4331 invoked by uid 1000); 20 Mar 2015 16:30:28 -0000 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Delivery-Agent: TMDA/1.1.12 (Macallan) X-Primary-Address: acm@muc.de X-detected-operating-system: by eggs.gnu.org: FreeBSD 9.x X-Received-From: 193.149.48.1 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 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.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:184043 Archived-At: Hello, Stefan. On Thu, Mar 19, 2015 at 04:56:16PM -0400, Stefan Monnier wrote: > >> you can handle fontification from 1,3, or 4 but not from 2. You need to > >> refine the system you use to keep track of whether we're within > >> a `union' so that it knows that position 2 is also "within a union". > > Well, sort of. The problem I'm facing is that in Dima Kogan's bug > > #19669, the following construct appears: > > 1. enum xxx_xxxx_xxxxxxxxxx_x > > 2. {XXX_XXXXXX_XXXX_XXX, > > 3. XXX_XXXXXX_XXX_XXX, > > 4. XXXX_XXXXX_XXXX_XXX, > > Note that the brace on L2 is on the same line as the first XXX_.... > > When the user types on line 4, 5, ... here, CC Mode sets the > > fontification region start to JUST AFTER THE { ON L2. It is essential > > that Font Lock doesn't change this. > There's your problem: your current setup needs the starting point to be > either before "union" or after the first open brace. > It breaks down if it's between the two. That's the problem you need to fix. Not really. CC Mode is quite capable of handling the Font Lock region starting at BOL2. The problem is, when that starting point needs to be after the brace on L2, Font Lock moves the starting point somewhere else, fouling up the font locking. This is proving surprisingly tough to fix. One place which is causing me puzzlement is in jit-lock-fontify-now. It's this bit: ;; The redisplay engine has already rendered the buffer up-to ;; `orig-start' and won't notice if the above jit-lock-functions ;; changed the appearance of any part of the buffer prior ;; to that. So if `start' is before `orig-start', we need to ;; cause a new redisplay cycle after this one so that any changes ;; are properly reflected on screen. ;; To make such repeated redisplay happen less often, we can ;; eagerly extend the refontified region with ;; jit-lock-after-change-extend-region-functions. (when (< start orig-start) (run-with-timer 0 nil #'jit-lock-force-redisplay (copy-marker start) (copy-marker orig-start))) The only way `start' can be before `orig-start' is on the first line of the fl region, and start is moved to BOL. Why is it necessary to go to all the expense of using `run-with-timer' rather than just fixing things inside `jit-lock-fontify-now'? What is the use case? The mechanism here, in particular the bit the attempts to avoid using this `run-with-timer' too often, is causing me pain. Could we not resolve the problem, whatever it is, by a less convoluted means? > Stefan -- Alan Mackenzie (Nuremberg, Germany).