; ps9/pgm5.cpx
;
; If x > y > z, returns the sum of x, y, and z.
; If x = y = z, returns x
; If x < y < z, returns the product of x, y, and z.
; Otherwise gives a divide-by-zero error.
; (tests that only one branch is evaluated)
(compex (x y z)
  (comp (- x y)
        (comp (- y z) (+ x (+ y z)) (/ y 0) (/ z 0))
        (comp (- y z) (/ y 0) x (/ z 0)
        (comp (- y z) (/ y 0) (/ z 0) (* x (* y z))))))