core.async_using_partial_continuation.scm

(use gauche.partcont)
(use util.queue)

(define-class <channel> (buf takes puts))

(define (chan)
  (make <channel> (make-queue) (make-queue) (make-queue)))

(define-syntax go
  (syntax-rules ()
    [(_ comm ...)
     (reset comm ...)]))

(define (>! c v)
  (if (queue-empty? (channel-takes c))
    (begin
      (enqueue! (channel-buf c) v)
      #f)
    (shift k
      (let ([taker (dequeue! (channel-takes c))])
        (enqueue! (channel-puts c) k)
        (taker v)))))

(define (<! c)
  (if (queue-empty? (channel-buf c))
    (shift k
      (let ([putter (dequeue! (channel-puts c))])
        (enqueue! (channel-takes c) k)
        (putter #f)))
    (dequeue! (channel-buf c))))

(define c (chan))

(go
  (let loop ()
    (let1 v (<! c)
      (print "received" v)
      (loop))))

(go
  (let loop ([i 0])
    (>! c i)
    (print "sent" i)
    (loop)))