TSPL 3rd ed., exercise 3.3.1

contloop.scm

;; Use call/cc to write a program that loops indefinitely, 
;; printing a sequence of numbers beginning at zero. 
;; Do not use any recursive procedures, and do not use any assignments.
(let ((kontp (call-with-current-continuation (lambda (k) (cons k 0)))))
  (let ((i (cdr kontp))
        (kont (car kontp)))
    (display i)
    (display " ")
    (kont (cons kont (+ 1 i)))))