Underflow

Underflow is a very fast implementation of McCarthy's amb operator for clojure. It has:

• a trampolining monad 'harness' that prevents stack overflow
• an evil, stateful, fast version of the same harness that is interface-compatible
• various macros for various amb operations using the harness

Underflow is not yet ready for prime time. Use with extreme caution.

Underflow began life as an implementation of Paul Graham's continuation-passing macros for Clojure, described in On Lisp. This is combined with the observation that continuation-passing is a monad (and in fact a final in the category of monads).