;; divisorsOf:  natnum natnum ' list-of-natnum
;; Returns all the divisors of divisee less than or equal to maxDivisor
;; including 1 and divisee, if it is less than maxDivisor.
(define (divisorsOf divisee maxDivisor)
  (local
      [;;divisorsOfdivisee:  natnum --> list-of-natnum
       ;;Returns all the divisors of divisee less than or equal to divisor
       ;; including 1 and divisee, if it is less than divisor.
       ;;Note that divisee does not need to be passed because it is 
       ;;in the closure of this function already.
       (define (divisorsOfdivisee divisor)
         (cond
           [(zero? divisor) empty]
           [(< 0 divisor) 
            (cond 
              [(= 0 (modulo divisee divisor)) 
               (cons divisor (divisorsOfdivisee (sub1 divisor)))]
              [else (divisorsOfdivisee (sub1 divisor))]) ]))]
    (divisorsOfdivisee maxDivisor)))



"divisorsOf test cases"

(equal? empty (divisorsOf 5 0))
(equal? (list 3 2 1) (divisorsOf 0 3))
(equal? (list 10 5 2 1) (divisorsOf 10 10))
(equal? (list 2 1) (divisorsOf 10 4))
(equal? (list 12 6 4 3 2 1) (divisorsOf 12 48))