;  Continuation-passing style examples


(define fact-cps
  (lambda (n k)
    (if (zero? n)
        (k 1)
        (fact-cps (sub1 n) 
                  (lambda (fact-n-1) 
                    (k (* n fact-n-1)))))))

(define list-copy
  (lambda (list)
    (list-copy-cps list 
                   (lambda (x) 
                    (display "The copied list is ") 
                    x))))

(define list-copy-cps
  (lambda (L k)  ;
    (if (null? L)
        (k '())
        (list-copy-cps (cdr L)
                       (lambda (copied-cdr)
                         (k (cons (car L) 
                                  copied-cdr)))))))

(define intersection-cps
  (lambda (los1 los2 k)
    (if
     (null? los1)
     (k '())
     (intersection-cps (cdr los1)
		       los2
		       (lambda (v)
			 (memq-cps (car los1)
				   los2
				   (lambda (memq)
				     (k
				      (if memq
					 (cons (car los1) v)
					 v)))))))))

(define memq-cps
  (lambda (sym ls k)
    (cond[(null? ls) (k #f)]
         [(eq? sym (car ls)) (k #t)]
         [else (memq-cps sym (cdr ls) k)])))