anchor.diff:      end,
   
       {call, Line, {remote, Line, {atom, Line, lists}, {atom, Line, seq}}, Args}.
  -
  -range -> signed_integer : '$1'.
   
   % list type
   list -> open_list match_expr close_list : {cons, line('$1'), '$2', {nil, line('$1')}}.
  
positive.code:     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.
  
  Terminals
      fn match open close open_block close_block
  
negative.code: 
  unwrap({_,V})   -> V;
  unwrap({_,_,V}) -> V.
  
  line(T) when is_tuple(T) -> element(2, T);
  line([H|_T]) -> element(2, H).
  