It turns out that Haystack is implemented in Adenine, a python like language that knows how to deal with RDF. In fact, it appears that RDF can be used to add metadata to the Adenine bytecodes (I'm not totally clear on this because the document that I read was not quite finished). Adenine also knows how to talk to Java (It's implemented in Java -- so its like an RDF-aware Jython+++). Haystack's UI framework is implemented in Adenine, and appears to use RDF for describing widgets (The framework document is long, and I just paged through it quickly -- I'll sit down for a thorough read later this week).

I'm really curious to see the Haystack developer release when it comes out. Maybe by the end of April we'll see both a Haystack and Chandler developer release.