anchor.diff:      binary binary_items binary_item bin_type_def bin_type
       prefix_op attribute
       obj_def obj_attrs obj_attrs_tail
  -    for_expr range signed_integer.
  +    for_expr range.
   
   Terminals
       fn match open close open_block close_block
  
positive.code: 
  unwrap({_,V})   -> V;
  unwrap({_,_,V}) -> V.
  
  unwrap_signed_integer({op, _Line, '-', {integer, _Line, Value}}) ->
      -Value;
  unwrap_signed_integer({op, _Line, '+', {integer, _Line, Value}}) ->
      Value;
  unwrap_signed_integer({integer, _Line, Value}) ->
      Value.
  
  line(T) when is_tuple(T) -> element(2, T);
  line([H|_T]) -> element(2, H).
  
negative.code: 
  bool_lit -> boolean             : {atom, line('$1'), unwrap('$1')}.
  
  range -> integer dotdot integer :
      Line = line('$2'),
      Start = unwrap('$1'),
      Stop = unwrap('$3'),
      Args0 = ['$1', '$3'],
  
      Args = if
  