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On Fri, 2003-01-17 at 21:50, Dare Obasanjo wrote:
> W3C XML Schema does a terribly poor job of mapping XML to objects and
> instead adds an extra layer of impedence mismatches that now have to be
> reconciled (what does derivation by restriction mean to objects or
> namespace restricted wildcards or the block attribute?).
OK! I thought you were thinking of the PSVI as a way to map XML to
objects...
I generally agree that WXS does a poor job, but not on all the examples
you mention :-).
I see derivation by restriction as a declaration for my applications: If
my complex type "restrict" is derived by restriction of a complex type
"super", I can tell that any class designed to cope with "super" will
know how to manage "restrict".
If you accept the fact that applications take decisions based on the
PSVI, this seems pretty usefull, isn't it? Otherwise, as far as markup
only is concerned, derivation by restriction of complex types is of no
use at all (it's more verbose than defining a complex type from
scratch).
> As for DTDs,
> their purpose would be specifying IDness so circular references can be
> effectively represented.
That's only a convention, and if I want to do the same using the
convention that "foo" is an ID and "bar" a reference, this doesn't look
like a gross hack to me!
Rather than using a XML schema language, it seems to me that some kind
of OO model (UML for instance) is the best tool to define such
mappings...
Eric
--
Did you know it? Python has now a Relax NG (partial) implementation.
http://advogato.org/proj/xvif/
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Eric van der Vlist http://xmlfr.org http://dyomedea.com
(W3C) XML Schema ISBN:0-596-00252-1 http://oreilly.com/catalog/xmlschema
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