From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Richard Stallman Newsgroups: gmane.emacs.devel Subject: Re: New hook before-region-change-functions wanted Date: Fri, 08 Sep 2017 18:22:15 -0400 Message-ID: References: <20170908144657.GA3463@ACM> Reply-To: rms@gnu.org NNTP-Posting-Host: blaine.gmane.org Content-Type: text/plain; charset=Utf-8 X-Trace: blaine.gmane.org 1504909484 7670 195.159.176.226 (8 Sep 2017 22:24:44 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 8 Sep 2017 22:24:44 +0000 (UTC) Cc: emacs-devel@gnu.org To: Alan Mackenzie Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Sep 09 00:24:40 2017 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 1dqRhW-0001fI-11 for ged-emacs-devel@m.gmane.org; Sat, 09 Sep 2017 00:24:38 +0200 Original-Received: from localhost ([::1]:47509 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dqRhd-0007Dx-Aq for ged-emacs-devel@m.gmane.org; Fri, 08 Sep 2017 18:24:45 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:35202) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dqRfH-0006B7-Od for emacs-devel@gnu.org; Fri, 08 Sep 2017 18:22:20 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dqRfG-0001mF-N2 for emacs-devel@gnu.org; Fri, 08 Sep 2017 18:22:19 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:49540) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dqRfD-0001ht-JN; Fri, 08 Sep 2017 18:22:15 -0400 Original-Received: from rms by fencepost.gnu.org with local (Exim 4.82) (envelope-from ) id 1dqRfD-0005LC-5g; Fri, 08 Sep 2017 18:22:15 -0400 In-reply-to: <20170908144657.GA3463@ACM> (message from Alan Mackenzie on Fri, 8 Sep 2017 14:46:57 +0000) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e 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:218040 Archived-At: [[[ To any NSA and FBI agents reading my email: please consider ]]] [[[ whether defending the US Constitution against all enemies, ]]] [[[ foreign or domestic, requires you to follow Snowden's example. ]]] > I would like to implement a new abnormal hook, > before-change-region-functions. It would be called just before a change > in the buffer's restriction (i.e., from widen and from narrow-to-region) > and each function on it would take two parameters, the beginning and end > of the new region being set. That kind of hook is pandora's box. It is too powerful, and would interact in complex ways. There will be many cases that are hard to implement correctly, or cause trouble. To implement this probably means future hassles for ourselves and for package developers. > The reason I want it is as part of the solution to bug #22983 > (syntax-ppss returns wrong result). I envisage two (or possibly more) > mutually independent caches, and a switch being made to the appropriate > cache when the region is changed. For this, all you need to do is record, for each alternative cashe, what buffer restrictions it corresponds to. Then use the right cache. That is a much safer way to do it. -- Dr Richard Stallman President, Free Software Foundation (gnu.org, fsf.org) Internet Hall-of-Famer (internethalloffame.org) Skype: No way! See stallman.org/skype.html.