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why 4.3 Structured Datatypes should wait

From: Dan Connolly <connolly@w3.org>
Date: 23 Oct 2002 13:37:53 -0500
To: www-webont-wg@w3.org
Message-Id: <1035398274.16867.7427.camel@dirk>

In short: because the XML Schema WG hasn't
yet decided how XML schema components fit
into URI space.

cf.

* TAG interested in progress on URIs for schema components (NUNs)
Dan Connolly (Thu, Oct 17 2002)
http://lists.w3.org/Archives/Public/www-xml-schema-comments/2002OctDec/0011.html

To elaborate a bit, yes, it would be nice to say...

 @prefix : <http://example/vocab#>.
 @prefix xs: <http://www.w3.org/???/xmlschema-components#>.

 :description rdfs:domain :Product;
   rdfs:range :ProductDescription.

 :ProductDescription a xs:ElementDeclaration;
   xs:name "desc";
   xs:typeDefinition [ a xs:ElementOnly;
     xs:contentModel [ xs:sequence (:name :photoref :blurb)].

so that
  <desc>
    <name>SuperCam</name>
    <photo ref="supercam1.jpg"/>
    <blurb>best camera since sliced bread!</blurb>
  </desc>

was an element of the class :ProductDescription.

In fact, there's a nifty UML diagram in the XML Schema spec,
  http://www.w3.org/TR/xmlschema-1/#component-diagram
and if our UML/OWL stuff works out, it should be a slam-dunk
to model stuff like schema components and properties,
and to say that XML Schema documents have the corresponding
RDF graph semantics.

But the bad news is: the current XML Schema specs
don't determine URIs for schema components such
as :ProductDescription. They get as far as
a (namespace name, localname, whichsortathing) tuple,
but they don't tell you the name for the thing.

I suppose we could write an expression for
"the element declaration schema component with
localname 'desc' in the namespace 'http://example/vocab' "
ala

  [ a xs:ElementDeclaration;
     xs:name "desc";
     xsmap:namespace <http://example/vocab>
  ]

but... is that what you really want to do?

So I'd like to keep 4.3 postponed; perhaps
our requirements document should show this
as a goal we didn't meet... or more straightforwardly:
let the issues list cite this message, and
let an update of the requirement document cite all the
postponed issues, as we go to last call.

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Wednesday, 23 October 2002 14:37:45 GMT

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