+ (if (or (zerop n) (zerop m))
+ 0
+ ;; KLUDGE: I'm going to assume that it was written this way
+ ;; originally for a reason. However, this is a somewhat
+ ;; complicated way of writing the algorithm in the CLHS page for
+ ;; LCM, and I don't know why. To be investigated. -- CSR,
+ ;; 2003-09-11
+ (let ((m (abs m))
+ (n (abs n)))
+ (multiple-value-bind (max min)
+ (if (> m n)
+ (values m n)
+ (values n m))
+ (* (truncate max (gcd n m)) min)))))