anchor.diff:  ///     RelationalExpression > ShiftExpression
   ///     RelationalExpression <= ShiftExpression
   ///     RelationalExpression >= ShiftExpression
  -///     RelationalExpression instanceof ShiftExpression 
  +///     RelationalExpression instanceof ShiftExpression
   ///     RelationalExpression in ShiftExpression
   ///
   /// ShiftExpression :
  
positive.code: Export  : 'export';
  Import  : 'import';
  
  /// The following tokens are also considered to be FutureReservedWords 
  /// when parsing strict mode  
  Implements : {strictMode}? 'implements';
  Let        : {strictMode}? 'let';
  Private    : {strictMode}? 'private';
  
negative.code:         // Check if the token is, or contains a line terminator.
          return (type == MultiLineComment && (text.contains("\r") || text.contains("\n"))) ||
                  (type == LineTerminator);
      }
  }
  
  @lexer::members {
  
      // A flag indicating if the lexer should operate in strict mode.
      // When set to true, FutureReservedWords are tokenized, when false,
      // an octal literal can be tokenized.
  