Consider the following 2 files. 'one' would not be effected by code changes
and reloading. 'two' would be effected.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-module(one).
-export([foo/0, start_link/0]).

start_link() ->
    spawn(?MODULE, foo, []).

foo() ->
    receive 
	{From, say} ->
	    From ! bar(),
	    foo()              %% a local fun
    end.

%bar() ->
%   "hello".


bar() ->
   "night".

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-module(two).
-export([foo/0, start_link/0]).

start_link() ->
    spawn(?MODULE, foo, []).

foo() ->
    receive 
	{From, say} ->
	    From ! bar(),
	    ?MODULE:foo()  %% an external fun
    end.

%bar() ->
%   "hello".


bar() ->
   "night".

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%