RDF considered optional

Paul Prescod paul at prescod.net
Thu Mar 18 14:30:31 GMT 1999

David Megginson wrote:
>  > I took it the same way. But doesn't that violate the principle of
>  > XML as being self-describing?
> First, there is no such published principle for XML itself, though the
> Namespaces spec provides an infrastructure for such a thing.

Debatably the principle of self-describing-ness is encoded in both the XML
declaration (unfortunately optional!) and the DOCTYPE declaration.

> Second, it in no way violates it, because if you recognise the
> namespaces/elements being used, you can still figure out that you're
> dealing with RDF (and if not, fat lot of good they'll do you anyway).

Wouldn't it be useful for a generic RDF processor (e.g. viewer, search
engine) to be able to recognize RDF in arbitrary documents?

Personally, I do feel that the optional RDF element is a bad idea. I have
had many bad experiences with "implied declarations" like <!DOCTYPE HTML
...> and <!SGML ...>. "Say what you are!" In this case the obvious way for
RDF elements to say that they are RDF elements without enforcing a
particular vocabulary would be to use attributes -- but that sounds like a
smelly old SGML-ish idea.

 Paul Prescod  - ISOGEN Consulting Engineer speaking for only himself

"If you were casting Bob Kane's character by disposition, you would 
never in a million years think Michael Keaton or George Clooney.
Good God: George Clooney? If you were casting Bob Kane's Batman, even 
the likes of Tim Roth or Christopher Walken would be much too 
lighthearted to play this demonic avenger."
	- http://www.salonmagazine.com/feature/1998/11/06feature.html

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