async.clj

(defn hello-loop [inbox outbox control]
  (go-loop []
    (alt! ;; choice
      inbox ([name] (do
                      (>! outbox (str "Hello" name)) ;; put
                      (recur))) ;; loop
      control nil)))

(let [in (chan) ;; construct a channel
      out (chan)
      ctrl (chan)]
  (hello-loop in out ctrl) ;; cons process
  (>! in "Michael") ;; put
  (println (<! out)) ;; take
  (close! ctrl))