anchor.diff:  %% @end
   %%-------------------------------------------------------------------------
   
  +foldr(F, A, []) when is_function(F, 3) ->
  +    A;
  +
   foldr(F, A, Node) when is_function(F, 3) ->
       foldr(F, A, [], Node).
   
  
positive.code: %% found within the first trie parameter.
  %% @end
  %%-------------------------------------------------------------------------
  
  merge(F, Node1, Node2) when is_function(F, 3) ->
      fold(fun (Key, V1, Node) ->
  
negative.code: %% @end
  %%-------------------------------------------------------------------------
  
  map(F, [] = Node) when is_function(F, 2) ->
      Node;
  
  map(F, Node) when is_function(F, 2) ->
      map_node(F, [], Node).
  
  