anchor.diff:  %% =====================================================================
   %% @equiv tree(Type, [])
   
  --spec tree(atom()) -> #tree{}.
  +-spec tree(atom()) -> tree().
   
   tree(Type) ->
       tree(Type, []).
  
positive.code: %% `erl_parse' tree; otherwise it returns `Node'
  %% itself.
  
  -spec unwrap(syntaxTree()) -> #tree{} | erl_parse().
  
  unwrap(#wrapper{tree = Node}) -> Node;
  unwrap(Node) -> Node.	 % This could also be a new-form node.
  
negative.code: %% @see data/1
  %% @see type/1
  
  -spec tree(atom(), term()) -> tree().
  
  tree(Type, Data) ->
      #tree{type = Type, data = Data}.
  