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Re: questions about rdfs:Datatype [Was: RE: Seeking normative definition of datatyping]

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Tue, 03 Dec 2002 09:47:33 +0000
Message-Id: <5.1.0.14.0.20021203094008.02f05448@0-mail-1.hpl.hp.com>
To: Art.Barstow@nokia.com
Cc: <www-rdf-comments@w3.org>

At 15:12 02/12/2002 -0500, Art.Barstow@nokia.com wrote:
> > From: ext Brian McBride [mailto:bwm@hplb.hpl.hp.com]
> > Sent: Monday, December 02, 2002 12:51 PM
>
> > >Which WD (and section) contains the normative definition of the
> > >semantics and syntax of RDF's new/proposed datatyping mechanism?
> >
> > This is not concentrated in a single WD, but is described in
> > a number of documents.
>
>Yuck!  I wonder if that's what TBL meant when he told the AC the RDF
>Core WG was clarifying M&S :-).

Ho Ho :(

We started with datatypes built as a layer on the core rdf langauge, i.e. 
datatype values were described using the previously defined 
primitives.  But this was changed to make datatyped values a core part of 
the language, at the same level as resource and simple literal.  It didn't 
seem to make sense to describe most of the core language in one document 
but say, go see this other doc or the datatypes bit, nor to duplicate the 
description.  Which is why we ended with this structure.  We figured that 
the primer would give a good cohesive overview of the whole topic and then 
the individual specs would provide the formal parts relevant to each spec's 
role.

Do let us know if you find this too confusing.


> > For an overview I suggest the primer.  The syntax is described
> > in the syntax doc, the concept of datatyping in the concepts doc, the
> > schema implications in the schema doc and formal semantics in
> > the semantics doc.
> >
> > You may find the specific links in
> >
> >
> > http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Nov/0527.html
> >
> > helpful.
>
>Thanks, that was helpful.
>
>However, where can I find a [preferably normative] example of how
>rdfs:Datatype is used (to define an application-specific datatype)?
>Also, how does an application define the lexical space for any
>rdfs:Datatype classes it defines?

What the WG has done is to define how to represent datatyped values in RDF, 
given there is a datatype meeting the constraints that RDF imposes defined 
somewhere.  One of the things we have not done is to provide an RDF 
mechanism for defining new datatypes.

So at present there is no mechanism to use rdfs:Datatype to define new 
datatypes nor to describe the lexical space of a datatype.

If you feel this is needed, then I'd be happy to add this to the list of 
issues that a future WG should consider.

Brian
Received on Tuesday, 3 December 2002 04:46:08 GMT

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