http://lemonodor.com/archives/000961.html A maybe-interesting paper by Aaron Mark Ucko, “Predicate Dispatching in the Common Lisp Object System, argues that predicate dispatching gives the best of the usual CLOS-style type dispatching and the ML/Haskell style pattern matching worlds. (defpdmethod hailstone (n) ((evenp... en-us http://bzdirectory.com/Predicate_Dispatch/0586601441.html Predicate Dispatch