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Re: variables as nodes? (re: XML Binding Format)

From: Dave Beckett <dave.beckett@bristol.ac.uk>
Date: Wed, 23 Mar 2005 14:53:18 +0000
To: Bijan Parsia <bparsia@isr.umd.edu>
Cc: howardk@fatdog.com, Yoshio FUKUSHIGE <fuku@w3.org>, 'RDF Data Access Working Group' <public-rdf-dawg@w3.org>
Message-Id: <1111589598.24655.44.camel@hoth.ilrt.bris.ac.uk>

On Tue, 2005-03-22 at 15:06 -0500, Bijan Parsia wrote:
...

> I'm no schema wonk (which is fine, btw :)), but looking at:
> 
>    <xs:element name="result">
>      <xs:complexType>
>        <xs:group minOccurs="0" maxOccurs="unbounded" ref="res:var"/>
>        <xs:attribute ref="xml:lang"/>
>      </xs:complexType>
>    </xs:element>
>    <xs:group name="var">
>      <xs:sequence>
>        <xs:any namespace="##targetNamespace" processContents="skip"/>
>      </xs:sequence>
>    </xs:group>
> 
> That processContents="skip" is a consequence of not having a fixed set 
> of names for the binding forms and that is unfortunate.
> 
> I would prefer for the element children of resutls to be fixed and data 
> bindable. ..

I'm not familiar with what you mean by "data bindable".  Some fixed
mapping between XML elements and ?? programming language concepts?
objects?  Could you give a little more context.

> ...
> I would also like to use xsi:type to enforce schema 
> processing of their children.

Does that mean having xsi:type on the children of <results> or do you
mean using an external typing method for the xml elements?  I was only
proposing inline xsi:type and nothing much type-related hidden in the
WXS file, leaving it to deal mostly with the VBR XML structure.


> Heck. It'd be nice to be able to distinguish bindings with a node vs. a 
> literal content. If we can't distinguish by attribute value, then i'd 
> be in favor of things like nodeVar, literalVar, etc.

That's the difference in RDF Terms - URI vs Blank Node vs Literal
(vs Datatyped literal?)

(RDF Term being from
http://www.w3.org/TR/2004/WD-rdf-sparql-query-20041012/#GraphPatterns
)

> I do not yet intend this as a proposal. I hope to flesh it out a bit 
> more. Deadlines and illness have interceded a bit.
> 
> But even the little bit more schema processing seems worth it to me.
> 
> I did some experiments with kendall on Dave's example transform scripts 
> to HTML tables, and it doesn't complicate them significantly (to my 
> eye). Also, you can, in XQuery, use typecase (or whatever it's called) 
> which might have optimization and safety advantages.

Maybe you could try the result2 forms I mentioned, attached to
http://lists.w3.org/Archives/Public/public-rdf-dawg/2004OctDec/0364.html

Dave
Received on Wednesday, 23 March 2005 14:54:02 GMT

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