1(define rec
2 (lambda (n stop)
3  (display n) (newline)
4  (if (= n 0) (stop 0)
5   (begin
6     (rec (- n 1) stop)
7     (display n) (newline)))))
8(rec 6 (lambda (x) '()))
9(call-with-current-continuation
10 (lambda (t) (rec 6 t)))
11
12