SimplePie_Parse_Date::parse

	 * self::month_pcre, and self::built_in
	 *
	 * @access private
	 */
	public function __construct()
	{
		$this->day_pcre = '(' . implode('|', array_keys($this->day)) . ')';
		$this->month_pcre = '(' . implode('|', array_keys($this->month)) . ')';

		static $cache;
		if (!isset($cache[get_class($this)]))
		{
			$all_methods = get_class_methods($this);

			foreach ($all_methods as $method)
			{
				if (strtolower(substr($method, 0, 5)) === 'date_')
				{
					$cache[get_class($this)][] = $method;
				}