docs: private void filterDef( PatternDescrBuilder< ? > pattern ) throws RecognitionException {
          BehaviorDescrBuilder< ? > behavior = helper.start( pattern,
                                                             BehaviorDescrBuilder.class,
                                                             null );
          try {
              String bName = label( DroolsEditorType.IDENTIFIER_PATTERN );
              if ( state.failed ) return;
  
              Token subtype = match( input,
                                     DRL5Lexer.ID,
                                     null,
                                     null,
                                     DroolsEditorType.IDENTIFIER_PATTERN );
              if ( state.failed ) return;
  
              if ( state.backtracking == 0 ) {
                  behavior.type( bName,
                                 subtype.getText() );
              }
  
              List<String> parameters = parameters();
              if ( state.failed ) return;
  
              if ( state.backtracking == 0 ) {
                  behavior.parameters( parameters );
              }
          } finally {
              helper.end( BehaviorDescrBuilder.class,
                          behavior );
          }
      }