anchor.diff:                            Value;
                         _ ->
                             case lasp_config:get(mode, state_based) of
  -                              delta_based  ->
  -                                  %% No broadcasting for the delta.
  -                                  Value;
                                 state_based ->
                                     Value;
                                 pure_op_based ->
  
positive.code: %% @doc Declare a new dataflow variable of a given type.
  -spec declare(id(), type()) -> {ok, var()}.
  declare(Id, Type) ->
      case lasp_config:get(mode, state_based) of
          delta_based ->
              gen_server:call(?MODULE, {declare, Id, Type}, infinity);
          state_based ->
              gen_server:call(?MODULE, {declare, Id, Type}, infinity)
      end.
  
  %% @doc Declare a new dynamic variable of a given type.
  -spec declare_dynamic(id(), type()) -> {ok, var()}.
  declare_dynamic(Id, Type) ->
      case lasp_config:get(mode, state_based) of
          delta_based ->
              gen_server:call(?MODULE, {declare_dynamic, Id, Type}, infinity);
          state_based ->
              gen_server:call(?MODULE, {declare_dynamic, Id, Type}, infinity)
      end.
  
  %% @doc Stream values out of the Lasp system; using the values from this
  %%      stream can result in observable nondeterminism.
  
negative.code:                           Value;
                        _ ->
                            case lasp_config:get(mode, state_based) of
                                state_based ->
                                    Value;
                                pure_op_based ->
  