gistfile1.scm

(load "/Users/colin/lib/test-manager/load.scm")

(define (factor-list index product factors)
  (cond ((< product 2)
         '())
        ((= 0 (modulo product index))
         (cons (cons index factors) (factor-list index (/ product index) factors)))
        (else
         (factor-list (+ index 1) product factors))))
        
(define (prime-factors product)
  (map car (factor-list 2 product '())))

(define-each-test
  (assert-equal (list 2) (prime-factors 2))
  (assert-equal (list 3) (prime-factors 3))
  (assert-equal (list 2 2) (prime-factors 4))
  (assert-equal (list 5) (prime-factors 5))
  (assert-equal (list 2 3) (prime-factors 6))
  (assert-equal (list 7) (prime-factors 7))
  (assert-equal (list 2 2 2) (prime-factors 8))
  (assert-equal (list 3 3) (prime-factors 9))
  (assert-equal (list 3 7 37 41) (prime-factors 31857))
)

(run-registered-tests)