在使用自我，父母，静态时如何使用? [英] when using self, parent, static and how?

问题描述

如果现在我对ststtic有所了解，现在我意识到我什么都不懂.我很困惑，我很难理解，但我做不到.有人可以在使用self，parent，static以及如何使用时解释此程序 我所做的所有最小更改都会改变结果，否则我将无法理解发生了什么. 非常感谢..

If by now I understood a little in ststic Now I realize I do not understand anything. I'm so confused and I struggle to understand and I can not. Someone can explain this program when using self, parent, static and how All the smallest change I do changes the result without that I can not understand what's going on. thanks a lot ..

来自 http://docs.php.net/language.oop5.late-static-的代码绑定

<?php
class A {
    public static function foo() {
        static::who();
    }

    public static function who() {
        echo __CLASS__."\n";
    }
}

class B extends A {
    public static function test() {
        A::foo();
        parent::foo();
        self::foo();
    }

    public static function who() {
        echo __CLASS__."\n";
    }
}
class C extends B {
    public static function who() {
        echo __CLASS__."\n";
    }
}

C::test();
?>

输出是:

A
C
C

推荐答案

您需要了解

You'll need to understand the concept of Late Static Binding, which determines when an identifier is bound to code/data. You can tell PHP to bind it early (self::) or later (static::).

将示例简化为两个类:

class A {
    public static function foo() {
        self::who(); // PHP binds this to A::who() right away
        static::who();  // PHP waits to resolve this (hence, late)!
    }

    public static function who() {
        echo __CLASS__."\n";
    }
}

class B extends A {
    public static function test() {
       self::foo();
    }

    public static function who() {
        echo __CLASS__."\n";
    }
}

B::test();

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