lazy channel

lazy_channel.clj

(require '[clojure.core.async :as a])

(defn pull-seq
  "Returns a (blocking!) lazy sequence read from a channel."
  [c]
  (lazy-seq
    (a/>!! c :ready)
    (when-let [v (a/<!! c)]
      (cons v (pull-seq c)))))

;; this is the producer
(defn produce [c]
  (a/go-loop [v 0]
    (when (= :ready (a/<! c))
      (println "channel is ready for more, working... ")
      ;; emulate work
      (a/<! (a/timeout (rand-int 100)))
      ;; browser
      (println "putting value " v)
      ;; send back a value and wait for more
      (a/>! c v)
      (recur (inc v)))))

(def c (a/chan))
(produce c)

(a/thread
  (doall (pmap println (pull-seq c))))

(a/close! c)