Undefined.php

<?php
/**
 * XPath 2.0 for PHP
 *  _                      _     _ _ _
 * | |   _   _  __ _ _   _(_) __| (_) |_ _   _
 * | |  | | | |/ _` | | | | |/ _` | | __| | | |
 * | |__| |_| | (_| | |_| | | (_| | | |_| |_| |
 * |_____\__, |\__, |\__,_|_|\__,_|_|\__|\__, |
 *       |___/    |_|                    |___/
 *
 * @author Bill Seddon
 * @version 0.9
 * @Copyright (C) 2017 Lyquidity Solutions Limited
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

namespace lyquidity\XPath2;

/**
 * Undefined (public)
 */
class Undefined
{
	const CLASSNAME = "lyquidity\XPath2\Undefined";

	/**
	 * Constructor
	 */
	private  function __construct()
	{ }

	/**
	 * @var Undefined $_value = new Undefined()
	 */
	private static $_value;

	/**
	 * Static constructor
	 */
	static function __static()
	{
		Undefined::$_value = new Undefined();
	}

	/**
	 * Value
	 * @var Undefined $Value
	 */
	public static function getValue()
	{
		return Undefined::$_value;
	}

	/**
	 * ToString
	 * @return string
	 */
	public function toString()
	{
		return "";
	}

	/**
	 * Magic function to return a string representation
	 * @return string
	 */
	public function __toString()
	{
		return $this->toString();
	}
}

Undefined::__static();

?>