you write a function that takes an AST and returns an AST, register it as a macro, and you're off to the races.
Insane and insanely brilliant. I'm not going to touch this until a lot of smoke blows over.
a clone of .NET's LINQ to SQL.
Sounds awesome.
This is completely uncharted territory for me. I'd love to hear how this pans out in a year or so. Seems like it's very powerful and can help a lot in shaping Python based Domain Specific Languages, but perhaps too powerful to the point where it'll end up a horrific and complicated bug magnet.