public function __construct($operator = 'datetime', $property = NULL)
 {
     parent::__construct($operator, $property);
 }
 public function __construct($property = NULL)
 {
     parent::__construct('length', $property);
 }
 public function __construct($property = NULL, $value = NULL)
 {
     parent::__construct('indexof', $property);
     $this->value($value);
 }
 public function __construct($point1 = NULL, $point2 = NULL)
 {
     parent::__construct('geo.distance');
     $this->points($point1, $point2);
 }