- From: Daniel Marques <dani@wiris.com>
- Date: Wed, 6 Nov 2013 12:32:09 +0100
- To: Ross Moore <ross.moore@mq.edu.au>, David Carlisle <davidc@nag.co.uk>
- Cc: Murray Sargent <murrays@exchange.microsoft.com>, Peter Krautzberger <peter.krautzberger@mathjax.org>, Frédéric WANG <fred.wang@free.fr>, Khaled Hosny <khaledhosny@eglug.org>, www-math@w3.org, Azzeddine LAZREK <a_lazrek@yahoo.fr>
Some of my conclusions: 1. The MathML 3 specification allows the dir at any level (remember the original question was related to MathML and LaTeX mutual conversion, thus math mode only). 2. We assume that UTF-8 is used for encoding Arabic or Hebrew characters (this is not related to RTL but worth to mention). 3. "As far as directionality is concerned, there is only two models; LTR and RTL. Other changes are merely differences in the notation used and this should be reflected in the content of the equations themselves (unless some form of abstraction is used)." (Khaled) 4. The \dir and \mathdir are already used as macro names. 5. The use of \style{direction:rtl}{x^2} is tempting but difficult to implement in TeX/LaTeX (although I do not care very much). 6. The use of {\mathdir{rtl}x^2} seems a quite good compromise solution. 7. Another option is to use \mathRTL and \mathLRT as a possible extension of the \RTL and \LTR commands of the bidi package. Dani -----Original Message----- From: Ross Moore [mailto:ross.moore@mq.edu.au] Sent: martes, 05 de noviembre de 2013 23:05 To: David Carlisle Cc: Murray Sargent; Peter Krautzberger; Frédéric WANG; Khaled Hosny; www-math@w3.org; Azzeddine LAZREK Subject: Re: RTL directionality in LaTeX Hi David, On 06/11/2013, at 8:07 AM, David Carlisle wrote: > On 05/11/2013 20:34, Ross Moore wrote: >> Directionality is a property of the math environment, not of the >> content in that environment > > > Usually but not always. After the review of use cases in the Arabic > math note, directionality in MathML3 is allowed at the level of > <mrow>, not just on the top level <math>. (Whether any particular TeX > or MathML rendering agent can support switching at that level is > another issue but the specification allows it.) OK. Thanks for that clarification. On 06/11/2013, at 8:43 AM, Khaled Hosny wrote: > On Wed, Nov 06, 2013 at 07:34:05AM +1100, Ross Moore wrote: >> I would vote for inserting something like \mathdir{rtl} > > Please note that \mathdir is already an Omega/Aleph/LuaTeX[1] > primitive name. > > Regards, > Khaled > > 1. In case of LuaTeX it is "hidden" by default, but formats my choose to > enable it. With this information, my advice would be to have a macro that effectively just sets a switch, in the usual TeX-like way, whose value is confined to a brace-delimited environment. Internal macro expansion either respects the value of that switch or ignores it. The details are left to developers to fill in. e.g. user-syntax could be: \[ x^2 + 2\,x + 1 = \begin{cases} (x+1)^2 & \text{ in Roman LTR script (LTR)}\\ {\setmathdir{rtl} (x+1)^2 } & \text{in Arabic (RTL)} \end{cases} \] Thus in Omega/Aleph/LuaTeX the primitive is set locally. Other formats would need to implement much more to get it right, or just gobble the argument and issue a warning message that directionality support is not yet available. This is in accordance, I think, with the discussion here: http://tug.org/pipermail/luatex/2012-December/003929.html where direct use of the primitive is delimited. > > David Hope this helps, Ross ------------------------------------------------------------------------ Ross Moore ross.moore@mq.edu.au Mathematics Department office: E7A-206 Macquarie University tel: +61 (0)2 9850 8955 Sydney, Australia 2109 fax: +61 (0)2 9850 8114 ------------------------------------------------------------------------
Received on Wednesday, 6 November 2013 11:32:37 UTC