/**
* Increment the current field.
*
* If the field does not exist, it will be set to this value.
*
* @see Expr::inc()
* @see http://docs.mongodb.org/manual/reference/operator/inc/
* @param float|integer $value
* @return self
*/
public function inc($value)
{
$this->expr->inc($value);
return $this;
}