Non-blocking version of core.async ping-pong game

ping_pong_go.clj

(ns ping-pong-go
  (:require [clojure.core.async :as async :refer [<! >!]]))

(defn ping [ch]
  (println "Ping")
  (go 
    (>! ch :ping)
    (<! (async/timeout 500))))

(defn pong [ch]
  (println "Pong")
  (go 
    (>! ch :pong)
    (<! (async/timeout 500))))

(defn return [ch]
  (go 
    (let [ball (<! ch)]
      (if (= ball :ping)
        (<! (pong ch))
        (<! (ping ch))))))

(defn play []
  (let [ch (async/chan 1)]
    (async/go-loop [cnt 0]
      (if (= cnt 0)
        (<! (ping ch))
        (<! (return ch)))
      (if (< cnt 10)
        (recur (inc cnt))
        (println "Game over!")))))