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Re: [namespaceDocument-8] RDF and RDDL

From: Sean B. Palmer <sean@mysterylights.com>
Date: Tue, 9 Apr 2002 11:47:48 +0100
Message-ID: <010401c1dfb3$ff6f2a60$08540150@localhost>
To: "Patrick Stickler" <patrick.stickler@nokia.com>
Cc: <www-tag@w3.org>
[...]
> > http://www.doctypes.org/meta/NOTE-xhtml-augmeta.html
>
> [broken link... any alternates?]

Argh! The entire doctypes.org has gone down, and Alexa doesn't have a
copy of that document. Thankfully the Google cache has it, so I've
published it to infomesh.net too:-

   <http://www.google.com/search?q=cache:www.
   doctypes.org/meta/NOTE-xhtml-augmeta.html>
   http://infomesh.net/2002/augmeta/

[...]
> Just <include> the RDF XML schema in the XHTML XML
> schema and you can achieve full validation.

According to:-

http://www.w3.org/TR/rdf-syntax-grammar/#section-Schemas

the only official schema for RDF is the BNF, and the non-normative XML
schema isn't even working yet. Since extensions to XHTML will most
likely require both working DTD and XSD modules, validation is not
going to be as easy as you appear to think it will be. Embedding
NTriples (well, Sandro's version) would be better from a validation
standpoint (you'd have to delimit it with <![CDATA[NTriples]]>).

In fact, the HTML specification says that it's legal to point to some
RDF externally, using either <link> or even <object> in the header. I
really don't think that embedding RDF is an architecturally clean
solution, for the following reasons:-

* Validation is difficult, if not impossible (already mentioned).
* RDF is not the center of the universe. If people want to embed Topic
Maps, SOAP graphs, or some as yet uninvented language (or perhaps an
alternate serialization of one of the above), what are they to do?
* Embedding huge amounts of data that legacy clients cannot read will
slow down loading - an unecessary problem given that the RDF can be
linked to.
* As Masayasu has mentioned, "the HTML WG will not recommend to use
'text/html' for this kind of documents". Mixing namespaces and sending
it to legacy processors is risky.
* XHTML 2.0 should have sufficient metadata mechanisms in it - while
I'm not saying that we all have to wait, I'm saying that it's an
option.

Linking to the RDF will remedy all of the problems mentioned above, so
architecturally it is the strongest choice. Augmenting the current
metadata mechanisms is also another choice. But please - don't embed.

--
Kindest Regards,
Sean B. Palmer
@prefix : <http://purl.org/net/swn#> .
:Sean :homepage <http://purl.org/net/sbp/> .
Received on Tuesday, 9 April 2002 06:48:44 GMT

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