intertwingly

<a xmlns:urn="http://purl.org/dc/terms/" 
   rel="urn:rights urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a" 
   href="http://example.com/terms_of_service.html" >

That looks a bit neurotic.

arrogant?

& ambiguous!

... unless somebody where to, you know, define some precedence rules...  lets see what I can come up with in 30 seconds or less.

In the stark and desolate context of XML+namespaces, an unbound prefix is a fatal error.  In the warm and forgiving context of HTML, perhaps an unbound prefix could signal... an IRI?

Even so, helpful conformance checkers might want to flag with a gentle warning cases when a CURIE is found where the prefix matches a URI scheme and the reference is other than a simple NCName.  Or an IRI is found with a simple ihier-part that is a NCName and an scheme that isn't bound as a prefix.  If either of these rules generate too many false positives or false negatives, then the rules get tweaked a bit and we iterate a few times.

Initially, browsers vendors need do nothing, after all the attribute is just a string.  Everything can be implemented at the implementation level in JavaScript, incurring a cost only when actually used.  Over time, and given enough demand, there might be value in paving over the cowpaths.

That’s just off the top of my head.  This problem is unfortunate, but solvable.

but where do the cowpaths lead?

It would be nice to be able to describe a video in a Web page with a standard syntax, and independently of which player is used (native, Flash, Java, Silverlight...).
I am thinking about an extension of the <video> tag to at least provide a thumbnail and a description, as I do not think this is already possible in HTML5 (or is it?).

It’s probably neurotic, but it certainly wasn’t meant to be arrogant. :) I’ll see if we can quickly deprecate the old syntax and replace it with something better.

Evan Goer
Yahoo! SearchMonkey Team

To be clear: it was Rob’s example that was neurotic, as defined by the link I provided, in that it used a single ‘prefix’ to mean two different things.

I would not expect such usages to be typical of RDFa.  The problems you are likely to see in real world usage are likely to be far more difficult to solve.  :-P

What is the !(real world)?

The real world is places where “Just” Use XML and “Just” use HTTP turns out to be way harder than one would think.

P.S.  Careful readers will note that many of the points in “Just” use XML also apply to HTML.

Thanks for making a precision on the abusive usage of “real world”. The set of initial conditions one puts on his/her system is part of the real world. Maybe the sentence would have been more meaningful in saying:

“The Web by its distributed nature creates issues which are far more difficult to solve than in a controlled environment.”

Fair enough.

Related: Manu Sporny: I’ve had a bit of time to look at Yahoo’s published vocabularies and I’m quite concerned by them and Yahoo!s general direction with vocabulary design.