-module(echo_server).
-export([start/0, print/1, stop/0]).


echo() ->
    receive
        {print, Msg} ->
            io:format("~w~n", [Msg]),
            echo();
        stop ->
            ok;
        _ -> echo()
    end.

start() ->
    case whereis(echo_server) of
        undefined ->
            register(echo_server, spawn(echo_server, echo, [])),
            ok;
        Pid when is_pid(Pid) ->
            {error, already_started}
    end.

print(Term) ->
    echo_server ! {print, Term},
    ok.

stop() ->
    echo_server ! stop,
    ok.