- From: Perry A. Caro <caro@Adobe.COM>
- Date: Tue, 20 Jul 1999 14:40:54 -0700
- To: rdf-dev@mailbase.ac.uk, www-rdf-comments@w3.org
- CC: xml-names-editor@w3.org
Hi! Apologies if this is a dead horse that's been beaten round the bush a few hundred times. I'm unclear on how to implement lookup and comparison of property names in RDF, in the context of XML namespaces. The XML namespace spec <http://www.w3.org/TR/REC-xml-names/> and the RDF spec <http://www.w3.org/TR/REC-rdf-syntax/> seem to be in good agreement, except for the following passage from the Formal Grammar for RDF section of the RDF Spec: p is the expansion of the namespace-qualified tag name (Generic Identifier) of E. This expansion is generated by concatanating the namespace name given in the namespace declaration with the LocalPart of the qualified name. It's this business about concatanating that worries me. The XML namespace spec never mentions concatanation as a valid mechanism. Indeed, the non-normative appendices seem to imply that the expansion of qualified names should be treated as ordered pairs. Consider the following RDF examples: <rdf:RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:foo="http://www.adobe.com/schema/property_"> <rdf:Description about=""> <foo:bar>a value</foo:bar> </rdf:Description> </rdf:RDF> vs. <rdf:RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:foo="http://www.adobe.com/schema/"> <rdf:Description about=""> <foo:property_bar>a value</foo:property_bar> </rdf:Description> </rdf:RDF> According the XML Namespace spec Appendix A.3, these two XML fragments generate non-equivalent Expanded Element Types: <ExpEType type="bar" ns="http://www.adobe.com/schema/property_"/> vs. <ExpEType type="property_bar" ns="http://www.adobe.com/schema/"/> However, the RDF spec seems to suggest that both of the above RDF fragments will generate the same dataset of triples, namely: {http://www.adobe.com/schema/property_bar, "", "a value"} ...which suggests that the two expansions are equivalent. Which is right? Am I reading too much into Appendix A.3? Is the concatanation mechanism suggested by RDF (and WebDAV, for that matter), a deviation from the XML namespace spec? Perry
Received on Tuesday, 20 July 1999 17:42:14 UTC