FW: Offer of advice

Gershon and I did discuss the use of the xml:lang attribute for inferring directionality, and it seems to me that xml:lang could be useful for basic support of the bidi algorithm, but it may break down if it was used to handle the more complex cases of bidirectional text.

For instance, there might be cases where the default embedding level may not be equivalent to that of the language. For instance, in a primarily Arabic document there might be a single paragraph that is predominantly English (starts and ends in English, but with some Arabic content nested within), but the author of the article wishes the default embedding level to be right-to-left so that it flows consistently with the rest of the article, then an xml:lang attribute of "English" on that paragraph will contradict with the wishes of the author. Using a dir attribute of rtl would meet his particular needs.

Also, the use of the xml:lang by itself may not be sufficient to determine directionality. Numeric sequences for instance are still rendered left-to-right in languages like Hebrew and Arabic, and an xml:lang setting of "Hebrew" would still impose a burden on the processor to understand that numeric runs would be rendered in a direction counter to the natural direction of the language. Tagging these numeric sequences with an xml:lang of "English" or another left-to-right language just to get left-to-right rendering would seem counter-intuitive to me.

One other thing, xml:lang does not have the notion of directional overrides - probably arguable how useful this feature actually may be - but nonetheless a feature of the bidi algorithm that would be difficult to reproduce using just the xml:lang attribute.

So, in my opinion, the use of the xml:lang attribute will probably be useful for translation purposes and possibly for basic support of directionality, but I believe that using the dir attribute will be a cleaner, more powerful and more explicit means for specifying directionality.

Ray

I think you two know each other already! I don't have time to participate in all of these discussions but Ray knows what requirements we came up with based on our conversations with customers, partners and experts and may have some thoughts to contribute on the discussions.

-----Original Message-----
From: JoAnn Hackos [mailto:joann.hackos@comtech-serv.com]
Sent: Thursday, March 16, 2006 6:28 AM
To: Paul Prescod; Don Day
Subject: RE: Offer of advice

Paul,
Could you put him in touch with Gershon so that he sees the debate going on about the dir attribute? I've attached the last of the email threads.
JoAnn

-----Original Message-----
From: Paul Prescod [mailto:paul.prescod@blastradius.com]
Sent: Tuesday, March 14, 2006 10:53 AM
To: JoAnn Hackos; Don Day
Subject: Offer of advice

I'd be glad to offer XMetaL's bidi expert for consultation on your bidirectionality discussions if this is of value to you. We went to considerable effort to research the best practices and state of the art before implementing our bidirectionality support.

Paul Prescod

dita-translation message