Key/Val Store in Elixir

gistfile1.ex

defmodule Db do
  use GenServer.Behaviour

  ## API

  def start() do
    :gen_server.start({:local, :db}, __MODULE__, [], [])
  end

  def store(key, val) do
    :gen_server.call(:db, {:store, key, val})
  end

  def fetch(key) do
    :gen_server.call(:db, {:fetch, key})
  end

  ## Callbacks

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

  def handle_call({:store, key, val}, _info, state) do
    new_state = Dict.put(state, key, val)
    {:reply, val, new_state}
  end

  def handle_call({:fetch, key}, _info, state) do
    {:reply, Dict.get(state, key), state}
  end
end