public function clearHost($opt = self::SCHEME | self::HOST | self::PORT | self::CREDENTIALS)
	{
		$scheme = ($opt & self::SCHEME) === self::SCHEME;
		$host = ($opt & self::HOST) === self::HOST;
		$port = ($opt & self::PORT) === self::PORT;
		$creds = ($opt & self::CREDENTIALS) === self::CREDENTIALS;
		if ($scheme) {
			$this->scheme->clear();
		}
		if ($host) {
			$this->host->clear();
		}
		if ($port) {
			$this->port->clear();
		}
		if ($creds) {
			$this->credentials->clear();
		}
		return $this;
	}