DEFREC ------ By Robert Smith DEFREC is a library for defining "top-level" mutually recursive functions. Example: (defrec (even (x) (declare (type unsigned-byte x)) (if (zerop x) t (odd (1- x)))) (odd (x) (declare (type unsigned-byte x)) (if (zerop x) nil (even (1- x))))) Now we can call EVEN and ODD.