[Patrick Stickler, Nokia/Finland, (+358 40) 801 9690, [log in to unmask]]
----- Original Message -----
From: "ext Jon Hanna" <[log in to unmask]>
To: <[log in to unmask]>
Sent: 11 December, 2002 14:31
Subject: Re: RDF typed literals and DC encoding schemes
> If even a way of expressing mappings towards canonical forms of datatypes
> were available it would go a long way.
It is very important to note that (a) not all datatypes define a
canonical lexical space and (b) canonicality of lexical forms is
completely irrelevant to RDF datatyping semantics.
Thus, even though there are certain practical benefits to having
canonical lexical forms, RDF has no need to say anything about them.
> > map in RDF - there doesn't even seem to be
> > a standardized way to point to a resource,
> > which would provide such a map somehow.
>
> Worse, to the extent that we can use xsi:schemaLocation with most uses of
> XML Schema datatypes we can't do so nicely with RDF because the RDF will
> treat it as a predicate (ironically it will then treat the value it gets as
> a literal of type anyURI instead of as a resource!).
While it is certainly a benefit to have RDF and XML Schema work well
together, it has to be appreciated that the xsi: vocabulary is specific
to XML Schema, not part of XML, and is an instruction for an XML Schema
parser, not an XML nor RDF parser, so it is not reasonable IMO to expect
an RDF parser much less an RDF reasoner to be able to deal with any usage
of xsi:schemaLocation in an RDF/XML instance.
That is not to say, however, that a vocabulary could/should not be
defined which would allow one to associate a datatype with one or
more schema or other resources which contribute to its definition.
> > This might be one of the reasons rdf-semantics
> > is that weak on datatype entailments.
>
> In fairness I think the real reason for this is that Rome wasn't built in a
> day. While the speed at which the RDF WG get around to looking at a
> particular issue may seem slow (a watched kettle never boils), the speed at
> which they are developing the framework is pretty breathtaking.
I can personally affirm that (for me at least) it has been no
less exciting than falling out of an airplane ;-)
Patrick
|