From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: Unbalanced change hooks (part 2) [Documentation fix still remaining] Date: Tue, 30 Aug 2016 18:01:39 +0000 Message-ID: <20160830180139.GC6672@acm.fritz.box> References: <7e1478b6-cf00-fcbf-8c24-43bdaa57e2b6@dancol.org> <415d1cca-f32c-624e-a4be-9aadcf8a0f17@dancol.org> <83inujbpek.fsf@gnu.org> <20160830171222.GA6672@acm.fritz.box> <5857ab7e-e85c-c6ae-ba1a-b1337ae57f2c@dancol.org> <83fupmm9ul.fsf@gnu.org> <67e1e007-c944-b91e-6c4b-b06b51beddc1@dancol.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1472580152 26529 195.159.176.226 (30 Aug 2016 18:02:32 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 30 Aug 2016 18:02:32 +0000 (UTC) User-Agent: Mutt/1.5.24 (2015-08-30) Cc: Eli Zaretskii , monnier@iro.umontreal.ca, emacs-devel@gnu.org To: Daniel Colascione Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Aug 30 20:02:27 2016 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1benMf-0006LN-HJ for ged-emacs-devel@m.gmane.org; Tue, 30 Aug 2016 20:02:25 +0200 Original-Received: from localhost ([::1]:50576 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1benMd-0008MG-6K for ged-emacs-devel@m.gmane.org; Tue, 30 Aug 2016 14:02:23 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:60866) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1benMT-0008Jq-46 for emacs-devel@gnu.org; Tue, 30 Aug 2016 14:02:14 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1benMN-00022Y-3a for emacs-devel@gnu.org; Tue, 30 Aug 2016 14:02:12 -0400 Original-Received: from mail.muc.de ([193.149.48.3]:41677) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1benMM-000220-RF for emacs-devel@gnu.org; Tue, 30 Aug 2016 14:02:07 -0400 Original-Received: (qmail 28546 invoked by uid 3782); 30 Aug 2016 18:02:06 -0000 Original-Received: from acm.muc.de (p548C605C.dip0.t-ipconnect.de [84.140.96.92]) by colin.muc.de (tmda-ofmipd) with ESMTP; Tue, 30 Aug 2016 20:02:03 +0200 Original-Received: (qmail 7036 invoked by uid 1000); 30 Aug 2016 18:01:39 -0000 Content-Disposition: inline In-Reply-To: <67e1e007-c944-b91e-6c4b-b06b51beddc1@dancol.org> 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: 193.149.48.3 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 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" Xref: news.gmane.org gmane.emacs.devel:206986 Archived-At: Hello, Daniel. On Tue, Aug 30, 2016 at 10:46:44AM -0700, Daniel Colascione wrote: > On 08/30/2016 10:42 AM, Eli Zaretskii wrote: > >> Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org > >> From: Daniel Colascione > >> Date: Tue, 30 Aug 2016 10:27:45 -0700 > >> +The region given to each of these functions is a conservative > >> +approximation of the region about to changed. After running the > >> +before-change-functions, Emacs will make zero or more fine-grained > >> +buffer changes and run after-change-functions for each. Do not expect > >> +before-change-functions and after-change-functions to be called in > >> +balanced pairs. > > The last sentence here is repeated afterwards, for no good reason. > > (Also, the markup is missing, but that's just an aside.) > I figured it was a good idea to highlight this fact directly in the > variable documentation blob. I can add a "see below" link. Why are you advocating this? It is not true. You _can_ expect b-c-f and a-c-f to be balanced in all but, perhaps, one occurrence per million. It happens so seldom that in practice, one can assume that b-c-f and a-c-f match completely[*]. You are describing the exception as though it were the typical case. [*] provided the exceptions are handled somehow. [ .... ] -- Alan Mackenzie (Nuremberg, Germany).