W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > August 2001

Re: RDF/XML Syntax - reifying using XML attributes only

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Wed, 22 Aug 2001 20:55:28 +0200
To: <w3c-rdfcore-wg@w3.org>
Message-ID: <MABBLGKMPIJFCKFGDBEPGEGFCAAA.jjc@hplb.hpl.hp.com>

Dave wrote:
> The various parsers do different things on this RDF/XML - which is
> wrong - so we must define one way or forbid it.

I agree with Dan C on this. The M&S grammar is clear. rdf:type takes a URI
reference as an attribute, everything else takes a string.

My view is, unless the implementation community have made plausible
mistakes, we should not consider changing the spec. To me, this mistake is
not sufficiently plausible.

If you want to give a URI for an rdf:subject property (or any other) it is
not hard (the rdf:resource attribute in a property element rule). I think
the change you are considering is just making life more difficult for parser
developers with insufficient compensation for rdf document writers. In
particular, I hope there are not people writing reified triples into
documents without any tool support. If there is tool support then the
current syntax is OK. If there isn't tool support then the model is overly
complex, and any syntax for an explicit reification is a nightmare.

To be clear:

<?xml version="1.0"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
  <!-- Test reified statement using attributes only -->
  <rdf:Description
rdf:type="http://www.w3.org/1999/02/22-rdf-syntax-ns#Statement"
                   rdf:subject="http://example.com/resource"
                   rdf:predicate="http://example.com/predicate"
                   rdf:object="literal" />
</rdf:RDF>


_:id1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#Statement> .
_:id1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject>
"http://example.com/resource" .
_:id1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate>
"http://example.com/predicate" .
_:id1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> "literal" .


Note this is different from both the other two versions we've had!
This is clearly an issue :-(.

Jeremy
Received on Wednesday, 22 August 2001 14:46:17 EDT

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