什么是新的静态? [英] what means new static?

问题描述

我在某些框架中看到了以下代码行:

I saw in some frameworks this line of code:

return new static($view, $data);

您如何理解new static?

推荐答案

在类的成员函数中编写new self()时，将获得该类的实例. 这就是self关键字的魔力.

When you write new self() inside a class's member function, you get an instance of that class. That's the magic of the self keyword.

所以:

class Foo
{
   public static function baz() {
      return new self();
   }
}

$x = Foo::baz();  // $x is now a `Foo`

即使您使用的静态限定词用于派生类，您也会得到Foo:

You get a Foo even if the static qualifier you used was for a derived class:

class Bar extends Foo
{
}

$z = Bar::baz();  // $z is now a `Foo`

(在某种意义上)如果要启用多态性，并且让PHP注意到您使用的限定符，则可以将self关键字替换为static关键字:

If you want to enable polymorphism (in a sense), and have PHP take notice of the qualifier you used, you can swap the self keyword for the static keyword:

class Foo
{
   public static function baz() {
      return new static();
   }
}

class Bar extends Foo
{
}

$wow = Bar::baz();  // $wow is now a `Bar`, even though `baz()` is in base `Foo`

这可以通过称为 后期静态绑定 ；请勿将其与关键字static的其他更常规用法混淆.

This is made possible by the PHP feature known as late static binding; don't confuse it for other, more conventional uses of the keyword static.

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