Jasper Op de Coul and I worked on megrok.rdf during the post-europython Grok sprint a few weeks ago. We had a few logistical problems concerning access to svn.zope.org, but yesterday Jasper finally managed to check in megrok.rdf:

http://svn.zope.org/megrok.rdf/trunk/

megrok.rdf is far from finished, and should be classified as a prototype. It has me excited for two reasons:

• if people were to hack on this I think Grok could quickly grow first-class RDF support without tremendous effort. What megrok.rdf can do for you is represent RDF subjects as models. These can then get views and adapters and such. RDF predicates can show up as object relations. These relations can be made to be traversable using grok.traversable().
• the way megrok.rdf works is quite similar to megrok.rdb, Grok's SQLAlchemy integration. This is not a surprise, as megrok.rdf's design is heavily influenced by my experiences with megrok.rdb. It still helps validate to me that Grok's way of exposing models makes a lot sense and is flexible. Grok has ZODB-backed Models and Containers, but it also has RDB backed Models and Containers and now, at least experimentally, RDF backed versions of the same.

A lot of work remains to be done. One thing we should do is to actually start documentation/doctests to solidify the approach. The way an RDF database is accessed (and integrated with Zope's transaction machinery) also needs attention.

I hope we can get some help from people interested in RDF. If people are interested, please join us at grok-dev.