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[html-bidi] Any bidi requirements for MathML (or MathMl in HTML)?

From: Bert Bos <bert@w3.org>
Date: Tue, 17 Aug 2010 15:33:08 +0200
To: public-i18n-bidi@w3.org
Message-Id: <201008171533.08266.bert@w3.org>
This is a somewhat vague question, and also rather late, given that 
MathML3 is as good as finished (it's a Proposed Recommendation), but I 
just wondered if anybody has thought about math...

The html-bidi[1] draft talks about requirements on HTML and CSS. It 
doesn't mention MathML, although the current MathML also has bidi 
support. And in the current plans for HTML5, MathML will be an integral 
part of the HTML language.

Are there no additional requirements on MathML?

The problem of bidi isolation at least doesn't seem to occur in MathML:

Section 3.1.5[2] of MathML3 describes the bidi features of MathML. It is 
possible to set the overall direction of a formula as well as the base 
direction of individual tokens.

Changing the overall direction acts almost like a mirror, e.g., "a + b" 
is written as "b + a" and superscripts (a²) are written on the left of 
their base (²a).

Tokens are symbols (+, =), numbers (12, 0.5), letters (x, y), words 
(sin, cos), or phrases ("such that," "theorem 1"). Setting a direction 
on tokens should rarely be needed, the inherited direction and the 
Unicode bidi algorithm are usually enough.

Unlike in HTML, each token is "directionally isolated" (in the terms of 
html-bidi WD), so a BDI attribute is not needed.

[1] http://www.w3.org/TR/2010/WD-html-bidi-20100304/
[2] http://www.w3.org/TR/MathML3/chapter3.html#presm.bidi

  Bert Bos                                ( W 3 C ) http://www.w3.org/
  http://www.w3.org/people/bos                               W3C/ERCIM
  bert@w3.org                             2004 Rt des Lucioles / BP 93
  +33 (0)4 92 38 76 92            06902 Sophia Antipolis Cedex, France
Received on Tuesday, 17 August 2010 13:33:36 UTC

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