- From: Dan Connolly <connolly@w3.org>
- Date: Thu, 30 Aug 2001 13:14:26 -0500
- To: Dave Beckett <dave.beckett@bristol.ac.uk>
- CC: w3c-rdfcore-wg@w3.org
Dave Beckett wrote: > > Addressing ACTION: 2001-08-24#8 Dave Beckett > Write up a proposed resolution for reifying using XML attributes > anly (sic) > > The RDF XML syntax defined in M&S allows properties to be written as > XML attributes in the Qname form, with values that are strings. > These are then turned into RDF statements with a string object. The > syntax also allows the rdf:type property to be used as an attribute > with the string value interpreted as a URI-reference. > > M&S defines explicitly other properties including rdf:subject, > rdf:predicate and rdf:object > http://www.w3.org/TR/REC-rdf-syntax/#formalReification > > In summary, these take as values: > Property Property Value > -------- -------------- > rdf:type URI-reference > rdf:subject URI-reference > rdf:predicate URI-reference > rdf:object URI-reference or literal Umm... I'm running into the same sort of use/mention issues here as are all over the RDF 1.0 spec. The fact that both XML attributes and RDF properties have values is one source of confusion. The values/objects of statements whose predicate is rdf:type are not constrained at all, as far as I know, let alone being constrained to a URI-reference. i.e. it's not the case that rdf:type rdfs:range xmlschema-datatype:URI-reference. right? But no matter... the test case you give is clear enough... > These can be used in this attribute abbreviated form since they match > the grammar propAttr or typeAttr (for rdf:type). > > Testing the attached example with parser implementations gives > different results for the statement values - some literals, > some URI-references. > > Thus, we need to clarify what is allowed here. > > Proposed clarification / resolution, test case. > > For properties encoded in XML attribute form, the attribute value > is interpreted as a literal for all properties except rdf:type > for which it is interpreted as a URI-reference. I'm not a big fan of this exception. While we're cleaning up this mess, I suggest we get rid of it. > The attached N-Triples defines the model produced by the attached > RDF/XML. > > Consequences: > rdf:subject and rdf:predicate if used in XML attribute form will > generate literal values which are presently forbidden (I think!) I think not. They might not make much sense, but they're not forbidden. > or maybe just very unexpected. quite possibly. > If you want to use rdf:subject, rdf:predicate properties, encode > them in the property element form (propElt). Yup. rdf:type too, I suggest. > rdf:object can be used but can only take a literal value. I suggest the expected results are: _: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" . -- Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Thursday, 30 August 2001 14:14:29 UTC