RDFa in HTML 5

Seeing as people are implementing RDFa parsers for text/html, I guess it 
would be good to have a specification that says how they should work.

http://www3.aptest.com/standards/rdfa-html/ doesn't answer the questions 
I'd want answered (e.g. in 
http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2009May/0102.html), 
and HTML 4 seems to make it impossible to express an answer. Some 
existing RDFa-in-text/html parsers are based on document models that 
closely match the DOM-like model used by HTML 5 (e.g. browser-based JS 
implementations, and some Python ones using an html5lib DOM, and maybe 
others), and the model used by HTML 5 can be implemented in a variety of 
other ways (e.g. unbuffered SAX) so it's not too restrictive, and so it 
seems like the most useful way to define RDFa-in-text/html processing.

I've not seen anyone else working on this, so I started writing a rough 
draft at <http://philip.html5.org/docs/rdfa/>. Some of it is copied from 
the RDFa-in-XHTML specification, and just tweaked to use some new 
definitions and to share concepts (like base and lang) with HTML 5 and 
to cope with text/html parsing (for xmlns:* attributes). The CURIE 
definitions are new, since I didn't see any existing document that 
defined them in an appropriate way.

There are several unresolved design issues (e.g. handling of 
case-sensitivity, use of xmlns:* vs other mechanisms that cause fewer 
problems, etc) - I haven't intended to make any decisions on such 
issues, I've just attempted to define the behaviour with sufficient 
detail that it should make those issues visible.

The current draft is far from complete or correct, but it shows roughly 
the way I'd like to have things defined (and I hope it's roughly the way 
that HTML5/WHATWG people would like it to be defined, in order to 
support implementers and to be testable), and maybe it could end up 
being useful for something, so I'm just throwing it out here for discussion.

-- 
Philip Taylor
pjt47@cam.ac.uk

Received on Monday, 18 May 2009 17:14:39 UTC