Re: bidirectionality with white-space collapsing

Richard Ishida wrote:
> The last line of says "This is best avoided by using the natural bidirectionality of characters instead of explicit embedding levels."
> My view is the following (also expressed perhaps slightly too succinctly in the FAQ that gave rise to the section in the CSS spec):
> 1. As a general principle it is best to put white space on the outside of markup rather immediately inside (ie. "XXX <markup>YYY</markup> ZZZZ" is better than "XXX<markup> YYY </markup>ZZZZ" or "XXX <markup> YYY </markup> ZZZZ"); and such an approach would solve the problem here.

I don't think you can say this "solve's the problem better" or that one
approach is better than another in this instance.
If the problem is the span sets text-decoration:underline, and you want the
space underlined, the solution is to remove the
space ahead of the markup and keep the space inside.

It should just make clear how it works, and the user needs to decide what they
are attempting to author.

> 2. Also, *if* the required presentation would be achieved by the bidirectional algorithm alone, and without markup that creates a new embedding level, then it is better to omit the directional attribute from the markup or remove the markup altogether (depending on how the markup is used) (which I think was what the CSS spec was trying to say). Eg. a single word in arabic or hebrew in an English sentence usually requires no markup to achieve the correct visual ordering in an XHTML document. You may want to surround it by something like a span element to apply font styling, but you don't need the dir attribute.

It is not clear to me that the statistics support this statement. Although the
majority of words and text end in strong direction characters, there are many
situations, especially if the text ends in punctuation or parentheses, where
having direction is helpful. I understand the alternative to add a format where
needed, but where is the harm in associating direction with a style, given that
not only direction but many other aspects of style are associated with language
and many authors will create styles for language, and it alleviates the need to
examine the endings of text runs and treat case by case.

> Hope that helps,
> RI
> ============
> Richard Ishida
> W3C
> contact info:

Tex Texin   cell: +1 781 789 1898  mailto:Tex at
Xen Master         XenCraft 
Making e-Business Work Around the World

Received on Wednesday, 10 March 2004 08:07:19 UTC