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<?php function gen_one_to_three() { for ($i = 1; $i <= 3; $i++) { // Note that $i is preserved between yields. yield $i; } } $generator = gen_one_to_three(); var_dump($generator); die; abstract class T { static public $instanses; final private function __construct(){ } public static function getInstance() { if (!(static::$instanses instanceof static)) { static::$instanses = new static; } return static::$instanses; } } class A extends T { static public $instanses; } class B extends A { static public $instanses; } $t = A::getInstance(); var_dump($t); $t1 = B::getInstance(); var_dump($t1); new B(); ?>

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