docs: private void parameters( ParameterSupportBuilder< ? > statement,
                               boolean requiresType ) throws RecognitionException {
          match( input,
                 DRL5Lexer.LEFT_PAREN,
                 null,
                 null,
                 DroolsEditorType.SYMBOL );
          if ( state.failed ) return;
  
          if ( input.LA( 1 ) != DRL5Lexer.RIGHT_PAREN ) {
              parameter( statement,
                         requiresType );
              if ( state.failed ) return;
  
              while ( input.LA( 1 ) == DRL5Lexer.COMMA ) {
                  match( input,
                         DRL5Lexer.COMMA,
                         null,
                         null,
                         DroolsEditorType.SYMBOL );
                  if ( state.failed ) return;
  
                  parameter( statement,
                             requiresType );
                  if ( state.failed ) return;
              }
          }
  
          match( input,
                 DRL5Lexer.RIGHT_PAREN,
                 null,
                 null,
                 DroolsEditorType.SYMBOL );
          if ( state.failed ) return;
      }