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: Wed, 10 Aug 2011 09:39:35 -0400 Message-ID: References: <877h6y7chn.fsf@fencepost.gnu.org> <831ux6cv5o.fsf@gnu.org> <87d3gpku3o.fsf@gnus.org> <834o1ypa2b.fsf@gnu.org> <87aabnn3mz.fsf@stupidchicken.com> <83mxfnwwyd.fsf@gnu.org> <87ipqbzogt.fsf@stupidchicken.com> <83liv7wqhe.fsf@gnu.org> <87liv75xsh.fsf@stupidchicken.com> <83k4arvx05.fsf@gnu.org> <87bow116je.fsf@stupidchicken.com> <83wrepyq3r.fsf@gnu.org> <87sjpar2l2.fsf@stupidchicken.com> <83aabizh94.fsf@gnu.org> <87vcu6b4rp.fsf@stupidchicken.com> <831uwuynfu.fsf@gnu.org> Reply-To: Eli Zaretskii NNTP-Posting-Host: lo.gmane.org X-Trace: dough.gmane.org 1312983589 4239 80.91.229.12 (10 Aug 2011 13:39:49 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Wed, 10 Aug 2011 13:39:49 +0000 (UTC) Cc: emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Aug 10 15:39:45 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 1Qr90b-0004QN-3d for ged-emacs-devel@m.gmane.org; Wed, 10 Aug 2011 15:39:45 +0200 Original-Received: from localhost ([::1]:33308 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qr90W-0000Dc-Vz for ged-emacs-devel@m.gmane.org; Wed, 10 Aug 2011 09:39:40 -0400 Original-Received: from eggs.gnu.org ([140.186.70.92]:50544) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qr90T-0000DW-DQ for emacs-devel@gnu.org; Wed, 10 Aug 2011 09:39:38 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Qr90R-0002Yk-MJ for emacs-devel@gnu.org; Wed, 10 Aug 2011 09:39:37 -0400 Original-Received: from fencepost.gnu.org ([140.186.70.10]:40323) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qr90R-0002Yg-Iv for emacs-devel@gnu.org; Wed, 10 Aug 2011 09:39:35 -0400 Original-Received: from eliz by fencepost.gnu.org with local (Exim 4.71) (envelope-from ) id 1Qr90R-00051S-GE; Wed, 10 Aug 2011 09:39:35 -0400 In-reply-to: (message from Stefan Monnier on Wed, 10 Aug 2011 09:20:34 -0400) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 140.186.70.10 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:143106 Archived-At: > From: Stefan Monnier > Cc: emacs-devel@gnu.org > Date: Wed, 10 Aug 2011 09:20:34 -0400 > > >> Also, while I'm here. I re-suggest to change the default of > >> bidi-paragraph-direction to left-to-right, since I think that preserves > >> backward compatibility a lot better. > > You never explained what backward compatibility is alluded to here. > > Emacs has done only ever left-to-right until now. So if we use > right-to-left where left-to-right was needed, it's a regression, whereas > if we use left-to-right where right-to-left was needed it's not. You are judging this from the POV or a non-R2L reader, who doesn't really care about correct display of R2L text. From the POV of R2L readers, what Emacs did before v24 is a "regression", and the current behavior is the correct one. It is true that R2L text will be readable in Emacs 24 even with left-to-right paragraphs, whereas in previous versions it was illegible, but it still looks wrong to the R2L eye, and in some cases (like very long lines that mix R2L and L2R) it's downright annoying. It would be a real regression if Emacs would sometimes display strict L2R text as right-to-left paragraphs. But this is not the case. IOW, Emacs 24 explicitly breaks "backward compatibility" in this regard, and for a very good reason. Some applications need to adapt to that, true, but this adaptation is the remaining 10% of the long journey from 100% non-support of bidi to 100% support. > >> We can set it to nil in the major modes where we know it can be > >> useful, such as text-mode. > > What other modes will need this? > > No idea. Well, then how do we make sure that changing the default to left-to-right will not make things worse than leaving it at nil? The list of modes that need left-to-right paragraphs and do not yet get them due to inheritance from prog-mode is known (and currently very short), because people complained. Relying on similar complaints after changing the default to left-to-right is not the best idea, since the number of R2L users is much smaller than that of the other kind.