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Re: storing info in XSL-FO: new issue? [was: Draft TAG Finding:...]

From: Elliotte Rusty Harold <elharo@metalab.unc.edu>
Date: Wed, 21 Aug 2002 10:07:13 -0400
Message-Id: <p04330101b9894b0431e4@[]>
To: robin.berjon@expway.fr
Cc: www-style@w3.org

At 3:59 PM +0200 8/20/02, Robin Berjon wrote:

>First point: the same would not be true if instead of h1's that 
>document had used solely visual markup. It would be impossible to 
>differenciate between genuine section titles and user comment 
><p><font size='7'>Britney Sp34rs ROCKS, yay!!!</font></p>.

Not impossible, perhaps difficult, and the results would be 
imperfect. But it's not out of the question, unless you require 
absolute certainty, which I don't think this use case does. It is 
acceptable to make mistakes provided that most of the information is 
successfully conveyed.

You need to also remember that something being marked as an h1 is not 
an absolute guarantee that it is in fact intended as a level 1 
heading. Web designers can and do use the h1/h2/etc. elements to 
achieve visual effects. All systems including the current one are 

>Second point: it might have worked had the document used PopStarML 
>*and* if the user had access to a PopStarML UA. It might even have 
>worked great with the UA humming a few notes of a popular song by 
>each <singer> to skim over the list instead of reading the name. The 
>problem is, functional (X)HTML UAs is already not a given, so new 
>UAs for endless streams of new specialised vocabularies is unlikely 
>to be workable.

Absolutely, which is why I like style sheets and basic XML supporting 
UAs. When  a document is intended for presentation to a person, it 
makes sense to attach a stylesheet to teach the basic UA how to 
display the content to a person. Different classes of users may need 
different style sheets, or may require variations on the standard 
styles. For instance, Jakob Nielsen has recently written about the 
importance of not locking in the font size at the server. However, 
the adjustments for presentation need to be made in the stylesheets 
and the user agents. Requiring us to serve only a few, predefined 
vocabularies misses the whole point of separation of presentation and 

>However, unaccessible content is useless. We are talking about 
>end-users here, not the ones that have fun reverse-engineering XML 
>vocabularies on rainy sunday afternoons.

XML+stylesheets is hardly unnaccessible.

>Your other post mentions (more or less directly) the possibility of 
>UAs able to get at the semantics of a new vocabulary, and using it. 
>That would be great as indeed if there were a way to associate 
>ArbitraryVocabulary with Ontology with MediumNeutralRendering (in 
>that order) then we'd have a much better Web.

Browsers don't normally need to get at the deep semantics of a 
document. Other tools may need this, and in fact do this, sometimes 
with human help, and this is what I was thinking about. Mostly, I was 
objecting to the claim that documents and markup have no meaning in 
the absence of prior agreement.

But this is more than browser needs to do. A browser needs to figure 
out how to render the content in a document into a form suitable for 
display to the person it's presenting the document to. The default 
rendering using a basic CSS or XSLT stylesheet to a picture on the 
screen is adequate for most users. Browsers presenting documents to 
visually impaired users will need to do more work to figure out how 
the visual presentation should be translated to an audio or other 
format. This can be assisted by a stylesheet, or it can be done by 
intelligently guessing how to best map common visual metaphors into a 
different form. Neither solution is perfect. Neither is easy. Neither 
is useless. And both can be used.

| Elliotte Rusty Harold | elharo@metalab.unc.edu | Writer/Programmer |
|          XML in a  Nutshell, 2nd Edition (O'Reilly, 2002)          |
|              http://www.cafeconleche.org/books/xian2/              |
|  http://www.amazon.com/exec/obidos/ISBN%3D0596002920/cafeaulaitA/  |
|  Read Cafe au Lait for Java News:  http://www.cafeaulait.org/      |
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Received on Wednesday, 21 August 2002 10:30:59 UTC

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