From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: bidi-display-reordering is now non-nil by default Date: Tue, 02 Aug 2011 20:01:17 +0300 Message-ID: <834o1zbvdu.fsf@gnu.org> References: <20110731.082721.451360942.wl@gnu.org> <20110731.085115.40009301.wl@gnu.org> <877h6yanje.fsf@fencepost.gnu.org> <878vre95g3.fsf@fencepost.gnu.org> <87fwlm7fam.fsf@fencepost.gnu.org> Reply-To: Eli Zaretskii NNTP-Posting-Host: lo.gmane.org X-Trace: dough.gmane.org 1312304705 23365 80.91.229.12 (2 Aug 2011 17:05:05 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Tue, 2 Aug 2011 17:05:05 +0000 (UTC) Cc: emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Aug 02 19:05:01 2011 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1QoIOr-0000dy-01 for ged-emacs-devel@m.gmane.org; Tue, 02 Aug 2011 19:05:01 +0200 Original-Received: from localhost ([::1]:60229 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QoIOq-0007nc-Dy for ged-emacs-devel@m.gmane.org; Tue, 02 Aug 2011 13:05:00 -0400 Original-Received: from eggs.gnu.org ([140.186.70.92]:36678) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QoIOn-0007nI-VM for emacs-devel@gnu.org; Tue, 02 Aug 2011 13:04:59 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QoIOl-0002vm-Q3 for emacs-devel@gnu.org; Tue, 02 Aug 2011 13:04:57 -0400 Original-Received: from mtaout21.012.net.il ([80.179.55.169]:50348) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QoIOl-0002vW-Jc for emacs-devel@gnu.org; Tue, 02 Aug 2011 13:04:55 -0400 Original-Received: from conversion-daemon.a-mtaout21.012.net.il by a-mtaout21.012.net.il (HyperSendmail v2007.08) id <0LPB00E007E90E00@a-mtaout21.012.net.il> for emacs-devel@gnu.org; Tue, 02 Aug 2011 20:03:20 +0300 (IDT) Original-Received: from HOME-C4E4A596F7 ([84.228.48.51]) by a-mtaout21.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0LPB00DZ78PJUX60@a-mtaout21.012.net.il>; Tue, 02 Aug 2011 20:03:20 +0300 (IDT) In-reply-to: X-012-Sender: halo1@inter.net.il X-detected-operating-system: by eggs.gnu.org: Solaris 10 (beta) X-Received-From: 80.179.55.169 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:142717 Archived-At: > From: Stefan Monnier > Cc: emacs-devel@gnu.org > Date: Tue, 02 Aug 2011 11:34:21 -0400 > > I think it makes sense to change the default value of > bidi-paragraph-direction to left-to-right. > I expect there are fewer modes where bidi-paragraph-direction needs to > be set to nil than modes where it needs to be set to left-to-right. > Furthermore a left-to-right default value is safer in the sense of > having better backward compatibility and avoiding pathological > performance problems. I don't necessarily disagree, and doing that is a one-line change. But let's not do it just yet, for two reasons. First, we only discovered 2 kinds of affected modes for now: Org mode and the mail/news summary modes. So our expectations of the number of affected modes do not have enough data points to back them up. I think we should gather more, to be able to weigh the merits and demerits of this. Eventually, some modes will need to use non-default values of this variable, so it really is an issue with how many modes will have to do this or that change. Second, concealing the potential performance problems at this early stage would make the testing of the bidi code much less effective, because evidently it was not used enough in the 1.5 years it was available on the trunk, if such problems are only now get reported. The problem with Org mode, for example, made it obvious that one of the optimizations I introduced to prevent slowdowns is failing in several important use cases, and needs to be redesigned. If the paragraph direction in Org buffers was forced to left-to-right, who knows when this grave problem would be discovered and reported. The "backward compatibility problems" part, I don't understand. Can you explain what you are alluding to?