anchor.diff:  %% Clean up state table.
   state_stop() ->
       ets:delete(state).
  -
  -%% Create all possible next states and add them to the `state` table.
  -state_store_succ(#info{active = Active, state = State}) ->
  -    state_store_succ_aux(State, set_list(Active)).
  -
  -state_store_succ_aux(_State, []) -> ok;
  -state_store_succ_aux(State, [Proc|Procs]) ->
  -    ets:insert(state, {[Proc|State]}),
  -    state_store_succ_aux(State, Procs).
   
   %%%----------------------------------------------------------------------
   %%% Unit tests (to be moved)
  
positive.code: state_init() ->
      [].
  
  %% Remove and return a state.
  %% If no states available, return 'no_state'.
  state_pop() ->
  
negative.code: -define(RET_HEISENBUG, 2).
  
  %% Debug messages (TODO: define externally?).
  %%-define(DEBUG, true).
  
  -ifdef(DEBUG).
  -define(debug(S_, L_), io:format("(Debug) " ++ S_, L_)).
  