Self and Static in PHP

• The so-called lazy static binding, as the name implies, is called statically: the binding of the part to the left of the symbol is a delay, that is, it is no longer resolved to define the class in which the current method resides, but is computed at the actual run time.

class A {    public static function who() {        echo __CLASS__.PHP_EOL;    }    public static function test() {        self::who();    }    public static function test2() {        static::who();    }}class B extends A {    public static function who() {        echo __CLASS__;    }}B::test();//AB::test2();//B

Self and Static in PHP