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Re: Question about linking CSS to XML vocabularies

From: Dave Raggett <dsr@w3.org>
Date: Sat, 30 Dec 2006 11:47:25 +0000 (GMT)
To: Anne van Kesteren <annevk@opera.com>
Cc: James Justin Harrell <herorev@yahoo.com>, www-style@w3.org
Message-ID: <Pine.LNX.4.64.0612301107040.5325@holly>

On Sat, 30 Dec 2006, Anne van Kesteren wrote:

> Well, this gets back to the original point. Why would you send 
> proprietary markup languages over the web... You shouldn't.

The ability to render application specific XML data either via CSS 
or XBL is is arguably better than being forced to transcode the data 
into HTML or to represent it as data in a script. Another case for 
sending XML is where you want to provide declarative extensions to 
an existing standard, and intepret them via CSS and script. The 
extensions may later be standardized, but the flexibility to try 
things out before the standardization process is definitely 
valuable.

The CSS3 selectors spec provides a means for substring matching that 
can act as an alternative to the HTML class attribute. It is not an 
exact match, since it has different specificity, and it doesn't 
explicitly support the notion of whitespace separated lists of 
tokens, but it is good enough for the purpose.

Another point of flexibility is whether applications can extend CSS 
without having to wait for browsers to implement the extensions. The 
selectors API provides syntactic convenience in building a list of 
DOM nodes, but as far as I can see, it doesn't give developers the 
means to extend CSS with new properties.

I think we are lacking an interface to declare new CSS properties. 
This would involve such information as whether they inherit or not, 
what the initial value is, and how to parse the value, e.g. using 
the syntax used in the CSS specifications. Such an interface would 
make it easy to experiment with proposed extensions to CSS, such as 
the draft CSS3 speech module.

I did take a look at the Mozilla source code with a view to adding
support for the CSS3 speech properties, but it proved to be a much
bigger task to declare new properties than expected and something
that only someone intimately familiar with the Mozilla CSS code
base could manage.

A lightweight declarative means to declare properties that are 
interpreted via the getComputedStyle interface would be really 
valuable and something that was overlooked in previous work.

  Dave Raggett <dsr@w3.org> http://www.w3.org/People/Raggett
Received on Saturday, 30 December 2006 11:47:38 GMT

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