Ticks scheduler - Clojure core.async

ticks-scheduler.clj

(defmacro deftickscheduler [name ticks-per-sec & body]
  `(when-not *compile-files*
     (def ~name (let [ticks-per-sec# (/ 1000 ~ticks-per-sec)
                      running?# (volatile! true)]
                  {:var (var ~name)
                   :channel (a/go-loop []
                              (when @running?#
                                (let [start# (System/currentTimeMillis)
                                      _# (do ~@body)
                                      elapsed# (- (+ start# ticks-per-sec#) (System/currentTimeMillis))]
                                  (when (pos? elapsed#)
                                    (a/<! (a/timeout elapsed#)))
                                  (recur))))
                   :running? running?#}))))

(defn stop-scheduler [scheduler]
  (let [{:keys [var channel running?]} scheduler]
    (vreset! running? false)
    (a/close! channel)
    (.unbindRoot var)))