- From: Paul Prescod <paul@prescod.net>
- Date: Sun, 10 Nov 2002 15:31:29 -0800
- To: Tim Bray <tbray@textuality.com>, WWW-Tag <www-tag@w3.org>
Tim Bray wrote: > > ... > > Now the 2nd RDF assertions in the two RDDLs are in conflict. The reason > is that they involve 2 different namespaces, but the namespace doesn't > get into the RDDL. But it could, be cause we know the URI of the > namespace ("" - this is the namespace doc remember) so we can make > assertions about it. I would strongly encourage you to make it at LEAST a SHOULD that RDDL documents say explicitly what the namespace is. RDDL documents will and should get cached offline. There will be issues of trailing slashes that appear and disappear depending on the web server configuration. There will be case sensitivity issues. Some purists will add pound signs to namespace names and these may be (should be?) stripped in the interpretation of the relative URI. If I use the wrong URI to register a RDDL with the semantic web or XML web equivalent of Google, there should be enough information built-in for it to recover. And what about XSLT and CSS stylesheets (and in fact almost any other processor) which are just handed the document and told to do something useful with it. You're increasing the coordination costs if we also ahve to define a separate channel for passing the URI. Jonathan was proposing something like > > - "" has a property called strict-validation-schema whose value is L.dtd > - the nature of L.dtd is that it's a DTD It seems clear to me that independent of the contradiction issue, the _whole point_ of RDDL is to define relationships between the namespace and its associated files. If you don't use RDF in a way that would do that, then you should just use a a proprietary linking strategy or XLink. > and you get no contradictions. BUT, you get way more tangled-looking > syntax and it gets way harder to predefine a bunch of precooked purpose > vocabularies AND it gets harder to automatically detect the "purpose" > property. So this would be an example of the "RDF tax" that has for > example doomed the RDF version of RSS. First, could you please be more concrete about all of these? A syntax example would be helpful. I could guess but an RDF-in-XML expert may know short-cuts that I don't know. Also, is it harder to detect the purpose for an RDF processor or just a general-purpose XML processor with RDF knowledge? Second, this is just further evidence that RDF/XML is broken. On a project for a customer it would be appropriate to just hack around it. But on a W3C project it seems that the right thing to do is track down the people who can fix RDF/XML and get them to do so. If people who WANT to use RDF properly feel that they cannot, that is a serious issue. Finally, a whole 'nother strategy is to define a mapping from an optimized XML syntax into the RDF model. BTW, the 1.2 example is not well-formed: <rdf:description about="http://example.org/schemas/L.rng rddl:title="Relax NG Schema" rddl:nature rdf:resource="http://relaxng.org/ns/structure/1.0" rddl:purpose rdf:resource="http://www.rddl.org/purposes#validation" rddl:prose rdf:resource="#rng-prose" /> Paul Prescod
Received on Sunday, 10 November 2002 18:32:15 UTC