V() method
  /**
   * PARSE METHOD for V ¨ a|b|c|d|e|f|g|h|i|j|k|l|m|n|o|p
   *                        |q|r|s|t|u|v|w|x|y|z
   */

  Object V()
    {
    skipWhitespace();

    if( isVar(peek()) )
      {
      return makeString(nextChar());
      }
    return failure;
    }