code: private boolean processTrueOrFalse() {
  
          if (token.tokenType == Tokens.TRUE) {
              read();
  
              return true;
          } else if (token.tokenType == Tokens.FALSE) {
              read();
  
              return false;
          } else {
              throw unexpectedToken();
          }
      }
docs: Retrieves boolean value corresponding to the next token.
  
  @return   true if next token is "TRUE"; false if next token is "FALSE"
  @throws  HsqlException if the next token is neither "TRUE" or "FALSE"