Elixir簡單的wordcount小程式

簡單的小練習 程式碼中用三個erlang程式模擬mapper 一個程式模擬reducer
程式碼不難 只是簡單模擬了下 有興趣的可以看看^_^

    defmodule Wordcount do
       @moduledoc "simple wordcount program by fairjm@ituring"
       @nodecount 3

       def start(file) do
          s = self
          spawn(fn -> count(file,s) end)
       end

       defp count(file,caller) do
            s = self
            nodes = Enum.map(1..@nodecount,fn _e -> spawn(fn -> countLine end) end)
            count = File.stream!(file)
                    |> Enum.reduce(0,fn e,r -> send(Enum.at(nodes,:random.uniform(@nodecount)-1),{e,s});r+1 end)
            IO.puts("total count is #{count}")
            v = countDown(count,%{})
            nodes |> Enum.each(&(send(&1,Stop)))
            send(caller,v)
       end

       defp countDown(0,m) do
            IO.puts("ending")
            m
        end

       defp countDown(n,m) do
            receive do
                map -> countDown(n-1, Enum.reduce(map,m,fn {k,v},r -> Map.put(r,k,Map.get(r,k,0)+v) end)) 
                after 5000 -> countDown( n-1 , m)
            end
       end

       defp countLine do
            receive do
                {line,caller} ->
                    IO.puts("#{inspect(self)} is doing work")
                    m = line 
                        |> String.strip
                        |> String.split(" ")
                        |> Stream.filter(&(String.length(&1) > 0))
                        |> Enum.reduce(%{},fn e,r ->
                                                    case r[e] do
                                                        nil -> Map.put(r,e,1)
                                                        v   -> Map.put(r,e,v+1)
                                                    end
                                            end
                                        )
                    send(caller,m)
                    countLine
                Stop ->
                    IO.puts("#{inspect(self)} quits")
                _other ->
                    IO.puts("error message")
                    countLine
            end
       end
    end