From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Itai Berli Newsgroups: gmane.emacs.bugs Subject: bug#27525: 25.1; Line wrapping of bidi paragraphs Date: Tue, 4 Jul 2017 12:10:17 +0300 Message-ID: References: NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="001a11426464f3243405537a4271" X-Trace: blaine.gmane.org 1499159590 26125 195.159.176.226 (4 Jul 2017 09:13:10 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 4 Jul 2017 09:13:10 +0000 (UTC) To: 27525@debbugs.gnu.org Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Tue Jul 04 11:13:05 2017 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1dSJtI-0006Wz-Lx for geb-bug-gnu-emacs@m.gmane.org; Tue, 04 Jul 2017 11:13:04 +0200 Original-Received: from localhost ([::1]:39658 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dSJtO-00031G-3B for geb-bug-gnu-emacs@m.gmane.org; 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charset="UTF-8" I'd like to add that this behavior breaks the Unicode bidirectional algorithm (UBA), and hence invalidates Emacs' claim of full conformance, or indeed of weak conformance, for that matter (so-called 'implicit bidirectionality' -- see section 4.2 of the UBA specifications). The reason is that section 3.4 'Reordering Resolved Levels' of the algorithm states (I replaced the bullet points in the original by numbers): > * The characters are shaped into glyphs [...] *> * *The accumulated widths of those glyphs *(in logical order)* are used to determine line breaks. The Emacs line-wrapping algorithm does not use the logical order of the glyphs to determine line breaks, as evidence by the example given in my original post, which I shall link to again: http://imgur.com/Bckn7zP --001a11426464f3243405537a4271 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I'd like to add that this behavior breaks the Unicode = bidirectional algorithm (UBA), and hence invalidates Emacs' claim of fu= ll conformance, or indeed of weak conformance, for that matter=C2=A0(so-cal= led 'implicit bidirectionality' -- see section 4.2 of the UBA speci= fications).

The reason is that section 3.4 'Reorderi= ng Resolved Levels' of the algorithm states (I replaced the bullet poin= ts in the original by numbers):

> * The charact= ers are shaped into glyphs [...]
> *=C2=A0The accumulat= ed widths of those glyphs (in logical order) are used to determine l= ine=20 breaks.

The Emacs line-wrapping algorithm does= not use the logical order of the glyphs to determine line breaks, as evide= nce by the example given in my original post, which I shall link to again:= =C2=A0http://imgur.com/Bckn7zP
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