anchor.diff:  -spec list_building_revs(State :: record()) -> {ok, [rev_def()]}.
   list_building_revs(State) ->
       {ok, [RevDef || {_Pid, RevDef} <- State#state.workers, RevDef /= none]}.
  +
   -spec number_free_workers(State :: record()) -> {ok, non_neg_integer()}.
   number_free_workers(State) ->
       {ok, lists:foldl(
  
positive.code: %% Internal Function Definitions
  %% ------------------------------------------------------------------
  
  -spec schedule_build(State :: record()) -> {ok, NewState :: record()}.
  schedule_build(State) when State#state.next_to_build == none ->
      get_build_candidate(State);
  schedule_build(State) ->
      {ok, State}.
  
  -spec get_build_candidate(State :: record()) -> {ok, NewState :: record()}.
  get_build_candidate(State) ->
      case {
              queue:is_empty(State#state.wait_queue),
              queue:is_empty(State#state.main_queue)} of
          {true, true} ->
              {ok, State};
          _Other -> %%TODO
              {ok, State}
      end.
  
  -spec create_workers(WorkerNumber :: non_neg_integer()) -> 
      {ok, [{Pid :: pid(), none}]}.
  create_workers(WorkerNumber) ->
  
negative.code:     }).
  
  -type rev_def() :: {atom(), atom(), list()}.
  -type plugin_def() :: {PluginName :: atom(), PluginArguments :: [term()]}.
  
  %% ------------------------------------------------------------------
  %% API Function Exports
  