[gruseom]

There definitely seems to be a version of Greenspun's Tenth Rule for Erlang. But I think Greenspunning has gotten too bad a name – sometimes implementing a subset of a classical system is exactly what you ought to do, for example when your problem allows you to exploit certain invariants that don't hold in the general case, or for some reason using the classical system itself (Erlang in this case) is not an option.

[coffeemug]

Right! Rethink has an adhoc Erlang runtime for message processing, and an adhoc lisp for the query language. I'm both ashamed and proud of this at the same time :)