W3C home > Mailing lists > Public > www-rdf-interest@w3.org > April 2001

Re: RDF in XHTML

From: Murray Altheim <altheim@eng.sun.com>
Date: Thu, 19 Apr 2001 14:48:36 -0700
Message-ID: <3ADF5D34.3974B0AE@eng.sun.com>
To: Jonathan Borden <jborden@mediaone.net>
CC: RDF Interest <www-rdf-interest@w3.org>
Jonathan Borden wrote:
[...]
> Having made my way through the XHTML Modularization DTDs as well as, for
> example, James Clark's TREX Schema for XHTML, I'd say that the TREX Schema
> is strikingly less complex (and much more concise). If you claim that the
> DTDs are more complex than need be, I'd say the proof is in the pudding,
> that is to say the current evidence does not support this claim. Clearly
> there is work required to make namespaces play nice with modularized DTDs
> that _significantly_ adds to the DTD complexity. For example IE5 chokes
> trying to validate modularized XHTML as does XML Authority (the only
> validator up to the task in my experience is STG's). My impression is that
> these modularized DTDs are in fact quite complex. No?

No, what this suggests (and should suggest to any engineer) is that unless
the XHTML m12n DTDs are invalid (which I can assure you they're not), that
the products you mention are noncompliant with the XML specification. That
is surely the ONLY conclusion one can draw. Complex? Perhaps. I haven't
looked at the TREX Schema for XHTML, so I don't know if it has the same
features as the DTD version. XML Schema did not have the ability to mimic
some of the features found commonly in DTDs. Every grammar has its limitations.

> What I am suggesting is that by referencing a schema by the namespace URI
> (e.g. within a RDDL document), multiple namespace applications such as RDF +
> XHTML can schema validate and in a straightforward fashion.

Well, I haven't read "the Cambridge Communique" but my understanding is 
that one of the conclusions was that schema validation of RDF was quite
difficult. I'm sure somebody on this list will correct me, but I am under
the impression that an RDF schema validator is necessary to validate RDF.
I don't think XML Schema is up to that task.

Murray

...........................................................................
Murray Altheim                            <mailto:altheim&#x40;eng.sun.com>
XML Technology Center
Sun Microsystems, Inc., MS MPK17-102, 1601 Willow Rd., Menlo Park, CA 94025

      In the evening
      The rice leaves in the garden
      Rustle in the autumn wind
      That blows through my reed hut.  -- Minamoto no Tsunenobu
Received on Thursday, 19 April 2001 00:48:40 GMT

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