echo server written in erlang

echo_server.erl

-module(echo_server).
-export([run/0]).
-author('mythosil').

-define(PORT, 1986).
-define(TCP_OPTIONS, [binary, {packet, 0}, {active, false}, {reuseaddr, true}]).

run() ->
  Listener = listen(),
  accept_loop(Listener).

listen() ->
  {ok, Listener} = gen_tcp:listen(?PORT, ?TCP_OPTIONS),
  Listener.

accept_loop(Listener) ->
  Socket = accept(Listener),
  spawn(fun() -> recv_loop(Socket) end),
  accept_loop(Listener).

accept(Listener) ->
  {ok, Socket} = gen_tcp:accept(Listener),
  Socket.

recv_loop(Socket) ->
  case gen_tcp:recv(Socket, 0) of
    {ok, Data} ->
      gen_tcp:send(Socket, Data),
      recv_loop(Socket);
    {error, closed} ->
      ok
  end.