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Re: Proposed CR change to default bidi behavior for elements with dir

From: Aharon (Vladimir) Lanin <aharon@google.com>
Date: Mon, 2 Dec 2013 10:41:22 +0200
Message-ID: <CA+FsOYYR49PUG8hEJRPkoC5=GZJkmWWrRsDQ6aEetvTjt3qzww@mail.gmail.com>
To: Erika Doyle Navara <Erika.Doyle@microsoft.com>
Cc: "public-html@w3.org" <public-html@w3.org>, "member-i18n-core@w3.org" <member-i18n-core@w3.org>, Richard Ishida <ishida@w3.org>, Addison Phillips <addison@lab126.com>, "Sam Ruby (rubys@intertwingly.net) (rubys@intertwingly.net)" <rubys@intertwingly.net>, Paul Cotton <Paul.Cotton@microsoft.com>
Sorry I did not notice this sooner, but unfortunately, the changes in
the changes in http://html5.org/tools/web-apps-tracker?from=8282&to=8283)
a number of serious problems, as described in
https://www.w3.org/Bugs/Public/show_bug.cgi?id=23260#c20. I have suggested
fixes there.

On Tue, Nov 26, 2013 at 2:41 AM, Erika Doyle Navara <
Erika.Doyle@microsoft.com> wrote:

> As I've heard a number of statements of support (in person) and no
> objections, I have folded this change into the CR branch [1].
> Please note: since the time I posted the initial spec change for review
> [2], Ian has produced a more comprehensive change [3] that updates some
> descriptions I had missed and that changes <bdo dir="ltr|rtl"> to be
> directionally isolated (to be unicode-bidi: isolate-override instead of
> unicode-bidi: bidi-override), as further requested by the i18n WG [4]. This
> keeps the behavior of dir consistent across different elements and enhances
> the usability of bdo under common usage. It is this later change (from the
> WHATWG spec) that I have chosen to fold into CR (as well as override my
> original change in the HTML5.1 master branch).
> Please reply back with any comments or issues.
> Thanks,
> Erika
> [1]
> https://github.com/w3c/html/commit/ca1986c79c26e49f7781577021b090df159c4c7a
> [2]
> https://github.com/w3c/html/commit/efbf692e44fa3e6b9d66a0823fc2133ff1d18f1e
> [3]
> https://github.com/w3c/html/commit/cf3f3dbbc3a28e0b6f82d6395427c84b4bf489a8
> [4] https://www.w3.org/Bugs/Public/show_bug.cgi?id=23260#c17
> -----Original Message-----
> From: Erika Doyle Navara [mailto:Erika.Doyle@microsoft.com]
> Sent: Thursday, October 24, 2013 4:34 PM
> To: 'public-html@w3.org'; member-i18n-core@w3.org; Richard Ishida;
> Addison Phillips; Sam Ruby (rubys@intertwingly.net) (
> rubys@intertwingly.net); Paul Cotton
> Subject: Proposed CR change to default bidi behavior for elements with dir
> The I18N working group has requested [1] that bug 22326 [2] be addressed
> in the HTML5 CR timeframe. This bug represents the implementation of the
> I18N proposal [3] to change the bidi semantics of the dir attribute to
> imply isolation rather than embedding.
> The technical discussion so far has taken place on the WHATWG cloned bug
> [4], but here is a summary of the pro/con arguments (Richard/I18N members,
> please correct if I have missed or misrepresented anything):
> Pro (make dir="" imply unicode-bidi:isolate)
> ==========================================
> - HTML5 is consistent with  Unicode 6.3 spec (and other specs, like CSS3
> Writing Modes) in making isolation the default for all inline bidi text
> embeddings
> - Bidirectional text is easy and intuitive for web developers to implement
> correctly, and without needing to know anything about the intricacies of
> bidi algorithm
> - Drives browser implementation to make the web less buggy with bidi
> issues. Problems with existing legacy pages will be fixed automatically.
> - Easy transition period while browsers adopt new behavior (code will work
> better in browsers with the change, but work the same in browsers without)
> - Once a browser supports isolation, it is trivial to implement this
> change in semantics for dir (simple change to default style sheet)
> Con (dir="" continues to imply unicode-bidi:embed)
> ===========================================
> - Currently no implementations yet of this behavior
> Rebuttal: IE8-IE10 did a similar (but not identical) change, however, and
> there was little or no compat fallout, both according to IE bug records and
> also i18n community
> - Default isolation for dir potentially makes the new HTML5 <bdi> element
> seem redundant.
> Rebuttal: <bdi> element is still useful in cases when text of unknown
> direction is dynamically inserted to a page (because it has new HTML5
> dir="auto" value as default, which determines dir at run time). Perhaps we
> could even re-label <bdi> from "bidi isolate" to "bidi insert".
> ...given the favorable reasons outweighing the unfavorable, I have
> implemented this change in the HTML5.1 Nightly draft, and believe it merits
> porting over to the HTML5 CR draft as well:
> https://github.com/w3c/html/commit/efbf692e44fa3e6b9d66a0823fc2133ff1d18f1e
> Please reply with any objections. Otherwise, I will port this change to
> the CR draft within a couple weeks (11/6).
> Thank you,
> Erika
> [1]
> http://lists.w3.org/Archives/Public/public-html-admin/2013Oct/0015.html
> [2] https://www.w3.org/Bugs/Public/show_bug.cgi?id=22326
> [3]
> http://www.w3.org/International/wiki/Html-bidi-isolation#Proposal_A:_change_the_dir_semantics
> [4] https://www.w3.org/Bugs/Public/show_bug.cgi?id=23260
Received on Monday, 2 December 2013 08:42:10 UTC

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