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;; based on http://talks.golang.org/2012/concurrency.slide#50
(ns robpike
(:require [cljs.core.async :as async :refer [<! >! chan close!]])
(:require-macros [cljs.core.async.macros :as m :refer [go alt!]]))
(defn timeout [ms]
(let [c (chan)]
(js/setTimeout (fn [] (close! c)) ms)
c))
(defn fake-search [kind]
(fn [c query]
(go
(<! (timeout (rand-int 100)))
(>! c [kind query]))))
(def web1 (fake-search :web1))
(def web2 (fake-search :web2))
(def image1 (fake-search :image1))
(def image2 (fake-search :image2))
(def video1 (fake-search :video1))
(def video2 (fake-search :video2))
(defn fastest [query & replicas]
(let [c (chan)]
(doseq [replica replicas]
(replica c query))
c))
(defn google [query]
(let [c (chan)
t (timeout 80)]
(go (>! c (<! (fastest query web1 web2))))
(go (>! c (<! (fastest query image1 image2))))
(go (>! c (<! (fastest query video1 video2))))
(go (loop [i 0 ret []]
(if (= i 3)
ret
(recur (inc i) (conj ret (alt! [c t] ([v] v)))))))))
(go (println (<! (google "clojure"))))
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