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Re: bidi discussion list was: Bidi Markup vs Unicode control characters

From: Ognyan Kulev <ogi@fmi.uni-sofia.bg>
Date: Wed, 10 Aug 2005 10:50:29 +0300
Message-ID: <42F9B1C5.3000903@fmi.uni-sofia.bg>
To: Tex Texin <tex@xencraft.com>
Cc: Stephen Deach <sdeach@adobe.com>, Addison Phillips <addison.phillips@quest.com>, www-international@w3.org, Richard Ishida <ishida@w3.org>, Bert Bos <bert@w3.org>

Tex Texin wrote:
> Ogi,
> I think the short answer is no. "Direction" has a number of components
> to it.
> Instead of thinking of an instance of a single text string, consider a
> series of text runs, with direction changes.

I admit that I'm haven't read much about bidi.  I just try to talk with 
common sense.

> When the language changes, does the direction level increase, is it
> reduced, or is it a start of a new top-level direction setting? How does
> each run relate to the surrounding runs? (In terms of the bidi
> algorithm.)

XML elements already imply nesting of text runs.  Isn't that enough?

> Also, what is the layout direction, regardless of the language of each
> text run?
> For example, as you know in HTML, tables have a direction. Regardless of
> the language of each cell's contents, the placement of the cell (or
> column actually) is determined by the direction of the table.

<table> can use xml:lang too.

> Direction for a language can also be ambiguous. Chinese can be written
> lr-tb, rl-tb, tb-rl...
> (where l,r,t,b are left, right, top, bottom). The front page of some
> Chinese newspapers can use all 3 of those directions/layouts.

When stylesheet is not used, you already give up on controlling layout 
and you choose to use some default layout for elements.  So isn't enough 
if one of these directions (lr-tb, ...) is chosen as default for 
language?  I don't know if this is acceptable for Chinese.

> So xml:lang might be suggestive, but it is not explicit or informative
> enough to base bidi layout upon it alone.

My point is: isn't xml:lang enough for producing acceptable layout when 
there is no stylesheet?

Regards,
ogi
Received on Wednesday, 10 August 2005 07:42:54 GMT

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