mem.cljs

anonymous-gist.cljs

(defn memoize-async
  "Returns a memoized version of a referentially transparent function. The
  memoized version of the function keeps a cache of the mapping from arguments
  to results and, when calls with the same arguments are repeated often, has
  higher performance at the expense of higher memory use.
  http://stackoverflow.com/questions/24698536/"
  [f]
  (let [mem (atom {})]
    (fn [& args]
      (go
        (let [v (get @mem args lookup-sentinel)]
          (if (identical? v lookup-sentinel)
            (let [ret (<! (apply f args))]
              (print "MISS" args (contains? (set (keys @mem)) args))
              (swap! mem assoc args ret)
              ret)
            (do (print "HIT!") v)))))))