Question

abstract class base {
    abstract public function test();
    public function run()
    {
        self::test();
    }
}

class son extends base {
    public function test()
    {
        echo 1;
    }
}
son::run();

It reports:

Fatal error: Cannot call abstract
method base::test()

But son::test() works,why and is there a way to fix?

Answer 1

“self” is lexically scoped, that is, if you use “self” in a method of Base, “self” means “Base”, no matter how you call this method at run time. php5.3 introduced a new kind of dynamic binding, which, ironically enough, is called “static”. The following works as expected in php 5.3

abstract class base {
    abstract public static function test();
    static public function run()
    {
        static::test();
    }
}

class son extends base {
    static public function test()
    {
        echo 1;
    }
}
son::run();