code: public boolean nonConsumingMatch(ParserTokenType rhs) {
        ParserToken token = lookAhead(0);
        return token != null && token.type.isInstance(rhs);
     }
docs: Determines if the token at the front of the stream is a match for a given type without consuming the token.
  
  @param rhs The token type
  @return True if there is a match, False otherwise