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Re: n-triples for datatype values [was: Agenda for RDFCore WG Telecon 2002-10-18]

From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Date: Sun, 03 Nov 2002 10:28:22 +0000
Message-Id: <>
To: "Tim Berners-Lee" <timbl@w3.org>
Cc: "Jos De_Roo" <jos.deroo.jd@belgium.agfa.com>, <w3c-rdfcore-wg@w3.org>

My problem is that rational cannot be handled as an optimization of any of 
these others:  there are some values that rational can represent that 
cannot be represented exactly by the others (e.g. 1/3).  (This was an 
objection I had to XML schema datatypes, to which I never really received a 
satisfactory response, but that's another story.)

This idea of only allowing "extended by standards body work" seems to me at 
odds with the W3C's approach to extensibility in other areas.  In the case 
of RDF, we're allowing that certain entailments may not be available if the 
datatype mapping (lexical->value) is not understood by the software, but 
the framework is still usable for applications that don't need to 
understand those datatypes.  That seems like a good approach to me.

So, if in your software you see "foo"^^datatypeURI with some datatype URI 
you don't understand, you just keep the whole thing together and treat it 
as an opaque blob, equal to somne other instance of "foo"^^datatypeURI but 
different from "bar"^^datatypeURI or "foo"^^someOtherURI.


At 05:31 PM 11/1/02 -0500, Tim Berners-Lee wrote:
>I think fixed in this case means "a small number extended by standards body
>rather than 'anyone can make a new one".  Interoperability at the atomic
>level is important.  But maybe I am being near-sighted.  In languages like
>it is important to have a very well-defined common set of atomic datatypes,
>but the again the ability to make new ones is rather neat.
>I guess I could imagine the implementations of code for integer, real,
>floating point
>and rational arithmetic being handled as optimizations.
>----- Original Message -----
>From: "Graham Klyne" <Graham.Klyne@MIMEsweeper.com>
>To: "Jos De_Roo" <jos.deroo.jd@belgium.agfa.com>
>Cc: <w3c-rdfcore-wg@w3.org>; "Tim Berners-Lee" <timbl@w3.org>
>Sent: Friday, November 01, 2002 4:58 AM
>Subject: Re: n-triples for datatype values [was: Agenda for RDFCore WG
>Telecon 2002-10-18]
> > At 01:31 AM 11/1/02 +0100, Jos De_Roo wrote:
> > > > I feel that "^^", being syntactic, should only be usable with a
> > > > fixed set of type URIs.
> > >
> > >that's indeed better
> >
> > I have a concern with that.  For example rational values as described in
> > CC/PP.  I'm rather concerned that the type system would be closed.
> >
> > [later]
> >
> > Or does "fixed" in this context mean non-variable?  I have no problem with
> > that.
> >
> > #g
> >
> >
> > -------------------
> > Graham Klyne
> > <GK@NineByNine.org>
> >

Graham Klyne
Received on Sunday, 3 November 2002 06:00:22 UTC

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