anchor.diff:  -export([match/2, validate/1, triples/1, words/1, wildcard/1]).
   
   -export([join/1, feed_var/3, is_queue/1, systop/1]).
  +
  +-ifdef(TEST).
  +-compile(export_all).
  +-endif.
   
   -type topic() :: binary().
   
  
positive.code: -spec is_queue(topic()) -> boolean().
  is_queue(<<"$Q/", _Queue/binary>>) ->
      true;
  is_queue(_) ->
      false.
  
  
negative.code: %% limitations under the License.
  %%--------------------------------------------------------------------
  
  -module(emqttd_topic).
  
  -import(lists, [reverse/1]).
  