Breaking my brain with continuations.

generator.scm

(define (make-generator proc)
  (define restart #f)

  (define (generator)
    (call/cc
      (lambda (return-c)

        (define (return v)
          (set! return-c (call/cc
                           (lambda (restart-c)
                             (set! restart restart-c)
                             (return-c v)))))

        (if restart
          (restart return-c)
          (proc return)))))

  generator)

(define g (make-generator
            (lambda (return)
              (return "Hello, ...")
              (return "World!")
              (return "This is a strange test")
              (return "... of how you can hurt your brain")
              (return "... with continuations.")
              (let infinite-loop ()
                (return " (now we return this forever) ")
                (infinite-loop)))))

(display (g)) (newline)
(display (g)) (newline)
(display (g)) (newline)
(display (g)) (newline)
(display (g)) (newline)
(display (g)) (newline)
(display (g)) (newline)
(display (g)) (newline)
(display (g)) (newline)