switch.clj

(defn tapify [f & args]
  (as-> (chan) in
    {:in in
     :out (apply f in args)}))

(defn switch
  ([in taps control] (switch taps control (chan)))
  ([in taps control out]
    (go (loop [n -1]
          (let [[v c] (alts! [control in])]
            (if (= c control)
              (recur v)
              (do
                (if (not= n -1)
                  (do 
                    (>! (:in (taps n)) v)
                    (>! out (<! (:out (taps n)))))
                  (>! out v))
                (recur n))))))
    out))