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RE: xmlsch-04 values without lexical forms

From: <Patrick.Stickler@nokia.com>
Date: Mon, 28 Apr 2003 16:38:26 +0300
Message-ID: <A03E60B17132A84F9B4BB5EEDE57957B01B90D41@trebe006.europe.nokia.com>
To: <jjc@hplb.hpl.hp.com>, <bwm@hplb.hpl.hp.com>, <w3c-rdfcore-wg@w3.org>


I agree that we should reject the comments.

I think we are trying to look at this in too much detail. Insofar
as RDF is concerned, an XSD union datatype is just an rdfs:Datatype,
i.e., RDF doesn't see that it is a union datatype. That's irrelevant.

The behavior of the union datatype is the same as for any rdfs:Datatype.
It has a lexical space, a value space, and an N:1 mapping from lexical
to value space. Period. The fact that the datatype in question is
a union datatype and the ordering of the component datatypes is taken
into account as part of the realization of its L2V mapping is completely
irrelevant to RDF Datatyping.

Given an XSD union datatype, and a lexical form, that lexical form
maps to one and only one value -- insofar as it is used with RDF.

xsi:type has no relevance to RDF and therefore one cannot use it
within RDF/XML to force some other mapping other than defined by
the union datatype definition.

Patrick



> -----Original Message-----
> From: ext Jeremy Carroll [mailto:jjc@hplb.hpl.hp.com]
> Sent: 28 April, 2003 16:21
> To: Brian McBride; Jeremy Carroll; w3c-rdfcore-wg@w3.org
> Subject: RE: xmlsch-04 values without lexical forms 
> 
> 
> 
> 
> The comment asks us to reword concepts
> 
> [[
> A datatype mapping is a set of pairs whose first element 
> belongs to the
> lexical space of the datatype, and the second element belongs 
> to the value
> space of the datatype:
> 
> + Each member of the lexical space is paired with (maps to) 
> exactly one
> member of the value space.
> + Each member of the value space may be paired with any 
> number (including
> zero) of members of the lexical space (lexical 
> representations for that
> value).
> 
> ]]
> 
> to change "including zero" to "one or more", if we do this 
> then we have to
> change the lexical-to-value mapping from being a function which maps a
> string to the first value associated with it in an XML Schema 
> union, to
> being a relation, which maps a string to any of the values 
> associated with
> it. XML Schema provides a mechanism by which the appropriate 
> member of the
> set of associated values can be chosen; this mechansim is not 
> open to RDF
> datatyping.
> 
> I am increasingly inclined to urge rejection of both this 
> comment and the
> renaming to use XML Schema's terminology comment on the 
> grounds that we wish
> to be able to reuse XML Schema union datatypes without 
> reusing the whole XML
> Schema framework.
> 
> Jeremy
> 
> > -----Original Message-----
> > From: Brian McBride [mailto:bwm@hplb.hpl.hp.com]
> > Sent: 28 April 2003 15:12
> > To: Jeremy Carroll; w3c-rdfcore-wg@w3.org
> > Subject: Re: xmlsch-04 values without lexical forms
> >
> >
> > My reading of schema datatypes is that with a union type:
> >
> >    o a lexical form can be ambiguous - i.e. might map to 
> different values
> > depending on which component type is used to do the mapping
> >
> >    o the component types of a union are ordered by the 
> order they are
> > declared when defining the union
> >
> >    o by default the ambiguity is resolved by applying the first
> > type whose
> > lex space includes the literal
> >
> >    o the default can be overridden by using an xsi:type attribute
> >
> > In RDF we always use the default disambiguation rule.  If 
> you want to
> > override, use a more specific datatype in the rdf:datatype 
> attribute.
> >
> > I guess I'm missing something.
> >
> > Brian
> >
> > At 14:17 28/04/2003 +0200, Jeremy Carroll wrote:
> >
> >
> > >I am increasingly worried by
> > >
> > >http://www.w3.org/2001/sw/RDFCore/20030123-issues/#xmlsch-04
> > >
> > >see
> > >
> > 
> >http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2003Apr
/0281.html
> >
> >(it does not seem to have made it into www-rdf-comments yet)
> >
> >Jeremy
>
>
Received on Monday, 28 April 2003 09:38:31 EDT

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