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
pj...@cam.ac.uk
