When you write new self() inside a class's member function, you get an instance of that class. That's the magic of the self keyword.
So:
class Foo
{
public static function baz() {
return new self();
}
}
$x = Foo::baz(); // $x is now a `Foo`
You get a Foo even if the static qualifier you used was for a derived class:
class Bar extends Foo
{
}
$z = Bar::baz(); // $z is now a `Foo`
If you want to enable polymorphism (in a sense), and have PHP take notice of the qualifier you used, you can swap the self keyword for the static keyword:
class Foo
{
public static function baz() {
return new static();
}
}
class Bar extends Foo
{
}
$wow = Bar::baz(); // $wow is now a `Bar`, even though `baz()` is in base `Foo`
This is made possible by the PHP feature known as late static binding; don't confuse it for other, more conventional uses of the keyword static.
