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" 

But I'm not saying that.  Read more carefully and you'll see that I'm
stating that *in general* it is best to avoid spaces on the inside of tags.
Then I'm saying that such an approach happens to solve the problem here. I'm
not saying that this is a better solution than that mentioned below, just an
alternative.  I think you need to do one or the other, though.

> 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. 

Again, I'm only saying ***IF*** the bidirectional algorithm copes fine on
its own.  If you have a need for the markup, this is not a good solution.

>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.


I'm not clear how using styles will provide a better solution for the case
in hand.  You need markup to apply the styling, so you'd be forced to adopt
the solution of removing internal spaces.


> > 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 08:06:46 UTC