php面对对象之延迟静态绑定：static关键字

先看一段代码：

abstract class domainObject{    static $name = 'domain';    public static function create(){        return self::$name;    }}class document extends domainObject{    static $name = 'document';}var_dump(document::create());

运行结果：string ‘domain’ (length=6)
self被解析为定义create()的domainObject，而不是解析为调用self的document类；
通过引入延迟静态绑定概念，将上述代码中父类的self:: 替换为static::，

abstract class domainObject{    static $name = 'domain';    public static function create(){        return static::$name;    }}class document extends domainObject{    static $name = 'document';}var_dump(document::create());

运行结果即为：string ‘document’ (length=8)
延迟静态绑定可使php在子类中查找所有的属性、值