;; some recursive function definitions in Ruse

(def fact
  (fun (n) :
    (if (n == 0)
        then 1
        else (n * (fact (n - 1))))))

(print "5! is" (fact 5))

(def odd?
  (fun (n) :
    (if (n == 0)
        then False
        else (even? (n - 1)))))

(def even?
  (fun (n) :
    (if (n == 0)
        then True
        else (odd? (n - 1)))))

(def map
  (fun (f ls) :
    (if (null? ls)
        then nil
	else (cons (f (car ls)) (map f (cdr ls))))))

(print "odds:" (map odd? (list 1 2 3 4 5 6 7 8 8 10)))

(print "evens:" (map even? (list 1 2 3 4 5 6 7 8 8 10)))