- From: Jonathan Borden <jborden@mediaone.net>
- Date: Wed, 23 Jan 2002 00:37:05 -0500
- To: <www-rdf-comments@w3.org>
Graham Klyne wrote: " The forward transformation from QName -> URI is clear and unambiguous per the original RDF specification. It is the reverse transformation that is problematic. " To be clear, while I would prefer that a bidirectional mapping be possible, just as I would _greatly_ prefer that the RDF model <-> XML mapping be bidirectional and roundtripable, there are issues with the simple forward transformation. In particular the model XML Schema uses for use of a QName as a type specifier is that the namespace name/URI is like the 'base URI' of the schema (quotes because it is not quite that simple but nonetheless) and that the localname is used as a locator for the type declaration within the schema module. In URI terms, XML Schema thus treats the localname LIKE a fragment identifier. It is not exactly a fragment identifier for several reasons, namely that no fragment identifer syntax is (yet)defined for application/xml and particularly because the localname maps to the XML Schema "name" attribute which is not ot type ID. For this reason I have issues with the forward QName -> URI mapping if this is a simple string concatenation. For the vast majority of RDF namespaces, perhaps all of the deployed RDF namespaces, simple concatenation is exactly the same as treating the localname as a fragment identifier (it comes after the '#') but for XML namespaces in general this is not the case. RDF does not require its namespaces to end in '#' hence one of the reasons for the incompatibility. I cannot say for sure that this incompatibility is entirely the 'fault' of RDF (although the mapping is perhaps too simplistic), rather a breakdown in communications and coordination between the RDF WG and other WGs more intimately involved in XML activities. It is not important to me where this incompatibility gets fixed, and since it is a basic architectural issue I agree with Brian and Tim Bray that the TAG ought be involved in this issue. For that reason alone, I would prefer that the issue not be closed for the moment. Jonathan
Received on Wednesday, 23 January 2002 00:07:05 UTC