exactor

registry1.ex

defmodule Registry1 do
  use ExActor.GenServer

  definit do: initial_state(HashDict.new) 

  defcast create(name), state: names, do: put_name(names,name) 
 
  defcall lookup(name), state: names, do: reply(HashDict.fetch(names,name))

  def put_name(names, name) do
    if HashDict.get(names, name) do
      new_state(names)
    else
      {:ok, bucket} = KV.Bucket.start_link()
      new_state(HashDict.put(names, name, bucket))
    end
  end
end

registry2.ex

defmodule Registry2 do
  use GenServer

  def start_link(opts \\ []) do
    GenServer.start_link(__MODULE__, :ok, opts)
  end

  def lookup(server, name) do
    GenServer.call(server, {:lookup, name})
  end

  def create(server, name) do
    GenServer.cast(server, {:create, name})
  end

  def init(:ok) do
    {:ok, HashDict.new}
  end

  def handle_call({:lookup, name}, _from, names) do
    {:reply, HashDict.fetch(names, name), names}
  end

  def handle_cast({:create, name}, names) do
    if HashDict.get(names, name) do
      {:noreply, names}
    else
      {:ok, bucket} = KV.Bucket.start_link()
      {:noreply, HashDict.put(names, name, bucket)}
    end
  end
end