/**
* Constructor.
*/
public function __construct()
{
parent::__construct();
// We just put parenthesis around special characters.
$this->keys[self::EXTENDED_1] = '($)';
$this->keys[self::EXTENDED_2] = '(/)';
$this->keys[self::EXTENDED_3] = '(+)';
$this->keys[self::EXTENDED_4] = '(%)';
}
