anchor.diff:  %%-------------------------------------------------------------------------------------
   %% Constant dimensions
   %%-------------------------------------------------------------------------------------
  -eval({'?', Dim}, I, E, K, D, W, T) ->
  +eval({'?', Dim}, _I, _E, K, _D, _W, _T) ->
     lookup_ordinate(K, Dim);
   
   %%-------------------------------------------------------------------------------------
  
positive.code:   {Xi, T};
  
  eval(Xi, I, E, K, D, W, T) when is_list(Xi) orelse is_atom(Xi) ->
    {{D0, T0}, Dims} = eval1(Xi, I, E, K, [], W, T),
    tcache:find(Xi, K, Dims, W, T).
  
  %%-------------------------------------------------------------------------------------
  
negative.code: %%-------------------------------------------------------------------------------------
  %% Constant values
  %%-------------------------------------------------------------------------------------
  eval(Const, _I, _E, _K, _D, _W, T) when is_number(Const) orelse is_boolean(Const) ->
    {Const, T};
  
  eval({string, Str}, _I, _E, _K, _D, _W, T) ->
  