- From: Danny Ayers <danny.ayers@gmail.com>
- Date: Thu, 2 Nov 2006 21:44:11 +0100
- To: "Sean B. Palmer" <sean@miscoranda.com>
- Cc: "Dan Connolly" <connolly@w3.org>, public-grddl-wg <public-grddl-wg@w3.org>, www-archive@w3.org
- Message-ID: <1f2ed5cd0611021244r7eedbf3ex8beecef786d68ed6@mail.gmail.com>
On 02/11/06, Sean B. Palmer <sean@miscoranda.com> wrote: > > > This may be ok, but as it stands steps outside the grddl-wg's remit > > into TAG and (unchartered) RDF group's territory. > > Actually it doesn't. From a corollary of the definition of > application/xml in RFC 3023, it can be demonstrated that someone > publishing an RDF/XML document as application/xml is asserting the > triples therein. > > The argument is that the following: > > [[[ > An XML document labeled as text/xml or application/xml might contain > namespace declarations, stylesheet-linking processing instructions > (PIs), schema information, or other declarations that might be used > to suggest how the document is to be processed. For example, a > document might have the XHTML namespace and a reference to a CSS > stylesheet. Such a document might be handled by applications that > would use this information to dispatch the document for appropriate > processing. > ]]] - Section 3, http://www.ietf.org/rfc/rfc3023.txt > > Means that it is appropriate for a user agent to interpret an RDF/XML > document served as application/xml as RDF based on the namespace of > the root element. > What about this: <x:Something xmlns:x="http://example.org/things/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns# "> <rdf:type rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class /> </x:Something> Since such a behaviour is allowed, it follows that > an author/publisher of such a document must expect the triples therein > to be taken as asserted; therefore they are asserted. I think you're probably right about it being allowed for a particular consumer, I'm less convinced that it's reasonable for the author/publisher to expect it. For example, take - <smil xmlns="http://www.w3.org/2001/SMIL20/ <http://www.w3.org/1999/xhtml>" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"> <body>Some text</body> </html> My agent may key off the existence of the RDF namespace declaration - that's not forbidden by the RFC 3023 is it? So the publisher should have expected it to be See > http://lists.w3.org/Archives/Public/public-grddl-comments/2006OctDec/0019 > > > Content-Type: application/xml > > > > <html xmlns="http://www.w3.org/1999/xhtml " > > [...] > > XHTML, RDF/XML or both? > > XHTML. > > > Keying off the root element narrows things down considerably, but > > then RDF/XML doesn't mandate a specific root element. > > No, but this is an application/xml document. You must interpret it per > the application/xml specification, which says that one may dispatch by > following the namespace mechanism, whereby it is an XHTML document by > root namespace dispatch. As you state below, no such root namespace dispatch mechanism is defined. It doesn't say that you may use random > heuristics; therefore it cannot be an RDF/XML document. > > You can think of this as being an analogy to > rdfms-qnames-cant-represent-all-uris. The RDF syntax can't model all > possible RDF graphs. Likewise, neither can application/xml be the > carrier type for all possible syntactically valid application/xml > documents. > Unlike with the former problem, however, there is a > workaround: just use application/rdf+xml! Well quite! The publisher of the namespace doc with application/xml has decided not to - I wonder why? It could be argued that root namespace dispatch isn't documented as > being the primary mechanism for namespace dispatch, Rather a strong argument, I'd say. but it seems > common sense given that the root element encapsulates the entire rest > of the document; It does, but I haven't surveyed the exceptions - I believe XSLT offers one. moreover I would consider there to be overwhelming > tool support for it, and consensus amongst specificationeers seems to > be converging upon it. > It could be argued that the media type is totally irrelevant on the same grounds (I wouldn't be particularly convinced of the alleged facts in either case without a decent survey). In either case, it doesn't necessarily follow that such an approach is a good idea, and certainly not without some alternate specification on which to base interop. Cheers, Danny. -- http://dannyayers.com
Received on Thursday, 2 November 2006 20:44:22 UTC