;; Producer/Consumer-Problem mit synchronem Message-Passing

(define-record-type :buffer
  (really-make-buffer insert-channel remove-channel)
  buffer?
  (insert-channel buffer-insert-channel)
  (remove-channel buffer-remove-channel))

(define (make-buffer)
  (let ((insert-channel (make-sync-channel))
	(remove-channel (make-sync-channel)))
    (letrec
        ((empty
          (lambda ()
            (full (receive-sync insert-channel))))
         (full
          (lambda (value)
            (send-sync remove-channel value)
            (empty))))
      (spawn empty))

    (really-make-buffer insert-channel
			remove-channel)))

(define (insert buffer value)
  (send-sync (buffer-insert-channel buffer) value))

(define (remove buffer)
  (receive-sync (buffer-remove-channel buffer)))