cat_fsm.erl

-module(cat_fsm).
-export([start/0, event/2]).

start() ->
	spawn(fun() -> dont_give_crap() end).

event(Pid, Event) ->
	Ref = make_ref(), % won't care for monitors here
	Pid ! {self(), Ref, Event},
	receive
		{Ref, Msg} -> {ok, Msg}
	after 5000 ->
		{error, timeout}
	end.

dont_give_crap() ->
	receive
		{Pid, Ref, _Msg} -> Pid ! {Ref, meh};
		_ -> ok
	end,
	io:format("Switching to 'dont_give_crap' state~n"),
	dont_give_crap().