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: Wed, 10 Aug 2016 16:18:21 +0000 Message-ID: <20160810161821.GB3413@acm.fritz.box> References: <838tw7hyk2.fsf@gnu.org> <20160808195459.GD7208@acm.fritz.box> <83tweugeu9.fsf@gnu.org> <20160809163814.GD4893@acm.fritz.box> <83inv9hkjd.fsf@gnu.org> <83h9ashfgx.fsf@gnu.org> <831t1wharr.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1470845955 24899 195.159.176.226 (10 Aug 2016 16:19:15 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 10 Aug 2016 16:19:15 +0000 (UTC) User-Agent: Mutt/1.5.24 (2015-08-30) Cc: Stefan Monnier , emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Aug 10 18:19:11 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 1bXWDn-0006ML-Jf for ged-emacs-devel@m.gmane.org; Wed, 10 Aug 2016 18:19:11 +0200 Original-Received: from localhost ([::1]:42662 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bXWDk-00014m-FL for ged-emacs-devel@m.gmane.org; Wed, 10 Aug 2016 12:19:08 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:56866) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bXWDe-00010H-AX for emacs-devel@gnu.org; Wed, 10 Aug 2016 12:19:03 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bXWDZ-0004mw-9H for emacs-devel@gnu.org; Wed, 10 Aug 2016 12:19:01 -0400 Original-Received: from mail.muc.de ([193.149.48.3]:40039) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bXWDY-0004lj-Ve for emacs-devel@gnu.org; Wed, 10 Aug 2016 12:18:57 -0400 Original-Received: (qmail 2581 invoked by uid 3782); 10 Aug 2016 16:18:54 -0000 Original-Received: from acm.muc.de (p548C65E5.dip0.t-ipconnect.de [84.140.101.229]) by colin.muc.de (tmda-ofmipd) with ESMTP; Wed, 10 Aug 2016 18:18:52 +0200 Original-Received: (qmail 3666 invoked by uid 1000); 10 Aug 2016 16:18:21 -0000 Content-Disposition: inline In-Reply-To: <831t1wharr.fsf@gnu.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:206545 Archived-At: Hello, Eli. On Wed, Aug 10, 2016 at 07:03:04PM +0300, Eli Zaretskii wrote: > > From: Stefan Monnier > > Date: Wed, 10 Aug 2016 10:56:59 -0400 > > > AFAICT, this is what happens, indeed, > > Then the old text was right: it's called before ANY modification. > Convince Alan, and I will change it back. For what it's worth, I don't like the vagueness of the doc as it currently is, and I wouldn't be against changing it back _FOR 25.1_ We've got a bug, but it's not urgent enough to have to be fixed for 25.1. > > > except that the call to before-change-functions in some cases does not > > > precede the first modification of the series. IOW, by the time the > > > hook is called, some modifications were already done. > > Sounds like a bug. > I'm not convinced it's a bug. > > In any case, my point is that the doc should still say "before any > > modification" because that's really what the code *should* do. We could > > add a blurb in the doc saying that the before and after hooks may not be > > properly paired (neither in number of calls nor in the specific value of > > BEG/END), but we should still claim that they're both called for any and > > all modifications > Which is inaccurate when modifications are done in several separate > parts, and you already agreed it's okay to call the hooks only once. > So "for any and all modifications" is bound to draw fire from people > who take that at face value. Some while ago, I think you said that there is a systematic basis for when before-change-functions doesn't get called. Is that still your view? If so, let's document that system. If not, then let's fix the code so that it is systematic. -- Alan Mackenzie (Nuremberg, Germany).