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Re: XML+SVG, XML+CSS, XML+XSL (was Re: Bad News on IE6 XML Support)
- From: "Simon St.Laurent" <email@example.com>
- To: firstname.lastname@example.org
- Date: Sun, 09 Sep 2001 02:01:43 -0400
At 09:48 PM 9/8/2001 -0400, Winchel 'Todd' Vincent III wrote:
>Assuming that (1) "*still* separat[ing] content from presentation" and (2)
>"edit once, present everywhere" are the goals, and assuming further that
>what you mean above is that "content" = "(perhaps any) XML" and
>"presentation" = "SVG", then what is the difference between:
>XML (content) + SVG (presentation)
>XML (content) + CSS (presentation)
>and while we're at it . . .
>XML (content) + XSL (presentation)
I'd suggest that these two are very similar:
XML (content) + SVG (presentation)
XML (content) + XSL-FO (presentation)
In both of those cases, having an XML-based presentation vocabulary pretty
much demands a transformation in between.
The other choice is different:
XML (content) + CSS(presentation)
The difference involves more than the use of a non-XML syntax. CSS is very
different from both SVG and XSL-FO because it's not about creating a "CSS
document". CSS is about providing information for existing
documents. While you can include CSS properties in an (X)HTML style
attribute, most of the power in the CSS approach comes from its insistence
on decorating documents rather than being the documents.
It is possible, as Joshua Allen noted, to create "identity transforms"
which create something else which is then decorated with CSS, but the CSS
selectors model doesn't assume transformation in the sense of XSLT,
creating a new document from an old one. CSS selectors let you paint
additional presentation information onto an XML document without modifying
There are costs to that approach - you can't sort a list or table, or
perform computations - but there are also some substantial benefits. When
linking documents, you don't need to worry that the target of a link will
evaporate in the transformation used to present it. When scripting
documents, you don't need to worry about whether you're addressing an XML
element or some (potential multiple or zero) derivative of that element.
Decoration has less power but also avoids some of the hairier situations
created by the use of that power. For a lot of common document and even
data formatting situations, CSS is both adequate and easier. For the
creation of SVG documents or typesetting with XSL-FO, the decoration
approach isn't enough, and then I suggest people use higher-power tools,
I just can't bring myself to believe that using XSLT to generate (X)HTML
from XML is necessary or useful in cases where mere decoration is all
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