Re: [xsl] schema-1 (was something about keys, a long while ago)

Subject: Re: [xsl] schema-1 (was something about keys, a long while ago)
From: Eric van der Vlist <vdv@xxxxxxxxxxxx>
Date: Tue, 16 Oct 2001 09:26:13 +0200
David Carlisle wrote:

For us, just being able to code a simple "typed" match without jumping
through any syntactical hoops would certainly make the XSL easier to
understand and write.


It's no fun at all if people take the opposite side of a debate from me and then make such plausible sounding arguments that there's a chance they might even be right...


No, and I can try to help!

While I think that powerful and expressive schema languages are a progress, I also think that imposing them would be a regression.

Schema languages are not that new and I am still thinking that one of the main progresses of XML over SGML is that DTDs are no longer mandatory!

And I think that it's important to make sure we can continue to perform XSLT transformations without defining first a schema.



However I'm still not toally convinced. It seems to me relatively rare to have lots of different element names (would have been called eleemnt types in an earlier era) which all have the same schema type and all need to be processed in the same way. If they have the same internal structure and the same processing one wonders what's gained by calling them different names.

Given that you do have lost of xxx-date element names you have to
_somewhere_ mapo them all to date. You say you don't want a long list in
a template match  (or equivalenty one assumes a lot of individual
templates each calling a named "date" template) but the information has
to be somewhere, for example in a list of type assignments in the
schema, this doesn't seem so much easier to maintain.


No, and there could also be less disruptive ways of implementing this.


A schema validation, especially when it's creating a PSVI is nothing more than a transformation and instead of creating all this new APIs and complexity, I would have prefered if the W3C had used the existing infoset information items.


The datatype, for instance, could have been considered (at least for elements) as a xsi:type attribute added by the validation.

If it had been the case, matching all elements of type foo:date would just have been a match="*[@xsi:type='foo:date']" (with the issue of supporting QNames in XPath/XSLT which needs to be fixed anyway).

The case of attributes would have been more touchy (maybe the attributes were really a bad idea in XML, after all) but I am convinced we could find a way to express the PSVI by adding elements and attributes in a specific namespace instead of creating new information items...

Eric


David

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-- Rendez-vous à Paris pour une visite guidee de la nebuleuse XML. http://dyomedea.com/formation/ ------------------------------------------------------------------------ Eric van der Vlist http://xmlfr.org http://dyomedea.com http://xsltunit.org http://4xt.org http://examplotron.org ------------------------------------------------------------------------


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