Re: forest grammar/tree regular expression for RDF (fwd)

On Tue, 26 Jun 2001, pat hayes wrote:

> >On Sun, 24 Jun 2001, Dan Connolly wrote:
> >
> >(on Jonathan Borden's RELAXNG work...)
> >
> >(msg trimmed to focus on rdf:Description question)
> >
> > > > I have specified this as a RELAXNG schema for RDF
> > > > http://www.openhealth.org/RDF/RDF1.rng in terms of solidifying
> >the RDF XML
> > > > syntax under the issue:
> > > > http://www.w3.org/2000/03/rdf-tracking/#rdfms-formal-grammar
> > >
> > > Very nice!
> > >
> > > It has a few special cases that I don't think are necessary
> > > (e.g. rdf:value is just another propertyElement/propertyAttribute,
> > > and rdf:Description is just a typedNode) but other than
> > > that, it seems to be quite a compact and precise description of
> > > the RDF syntax.
> > >
> >
> >[...]
> >
> > > Production 4 is ambiguous, no?
> > >
> > > 4.type description =
> > >              rdf:Description[
> > >                      idAboutAttr?,
> > >                      bagIdAttr?,
> > >                      propAttr?,
> > >                      propertyElt*
> > >              ] |
> > >              typedNode
> > >
> > > <rdf:Description/> matches both alternatives, no?
> > >
> > > As I say, I don't see any need to special-case
> > > rdf:Description in the grammar.
> >
> >
> >If we take this reading of the syntax, then the presence of
> >rdf:Description asserts an rdf:type relationship between the described
> >resource and an rdfs:Class called rdf:Description.
> >
> >I've seen nothing in RDF elsewhere to support the claim that RDF defines
> >such a class; M+S is pretty clear that the rdf:Description construct is
> >pure encoding syntax.
>
> Dan, can you (briefly) elaborate on what you mean by 'encoding syntax' ?

I meant that it was solely concerned with RDF's angle-bracketted
representation; or rather, with one of the (possibly many) XML
representations of the RDF triples data structure. Other representations
of RDF in angle brackets (eg. using XLink) might not have anything
corresponding to rdf:Description.

Dan

Received on Tuesday, 26 June 2001 14:03:57 UTC