gistfile1.clj

(ns hoare.problem
  (:require [clojure.core.async :refer :all]))

(defn fan-in
  ([ins] (fan-in (chan) ins))
  ([c ins]
    (go (while true
          (let [[x] (alts! ins)]
            (>! c x))))
    c))

(defn service []
  (let [in (chan)
        out (chan)]
    (go (while true
          (let [val (<! in)]
            (>! out (str val " done")))))
    [in out]))

;; On the console I see messages coming from c
;; that have not been modified by the service;
;; furthermore they're coming out of order,
;; such as "b 9" before "b 8 done".
;; Don't know what's GO ing on here.
(defn test-fan-in []
  (let [[a-in a-out] (service)
        [b-in b-out] (service)
        c (fan-in [a-out b-out])]
    
    (go (while true
          (println "c:" (<! c))))
    
    (go (dotimes [i 10]
          (>! a-in (str "a " i))))
    
    (go (dotimes [i 10]
          (>! b-n (str "b " i)))))
  
  nil)

;