Callable Arrays
An callable array is an array with index 0 and 1. The first index is a string, that represents a valid class, or an object. The second argument is a string, which is a method name.
With such a configuration, it is possible to use that array as a callback: either with a static method call, or a normal method call.
<?php
class X {
static function foo() { echo __METHOD__;}
function goo() { echo __METHOD__;}
}
$callable1 = [new X, 'goo'];
$callable1(); // X::goo
$callable2 = ['X', 'foo'];
$callable2(); // X::foo
$callable3 = [X::class, 'foo'];
$callable3(); // X::foo
?>