/**
* This method tests the "covariant" method.
*/
public function test_covariant()
{
$p0 = IOption\Type::covariant(IOption\Type::some(IInt32\Type::zero()));
$this->assertInstanceOf('\\Saber\\Data\\IOption\\Type', $p0);
$p1 = IOption\Type::covariant(IOption\Type::none());
$this->assertInstanceOf('\\Saber\\Data\\IOption\\Type', $p1);
}
/**
* This method (aka "flatMap") binds the subroutine to the object within this option.
*
* @access public
* @static
* @param IOption\Type $xs the left operand
* @param callable $subroutine the subroutine function to be applied
* @return IOption\Type the option
*/
public static function bind(IOption\Type $xs, callable $subroutine) : IOption\Type
{
return $xs->__isDefined() ? IOption\Type::covariant($subroutine($xs->item(), IInt32\Type::zero())) : IOption\Type::none();
}
