如何在新创建的对象上链接方法?

2021-12-30 00:00:00 method-chaining constructor php new-operator

我想知道是否有办法在 PHP 中为新创建的对象链接方法?

I would like to know whether there's a way to chain methods on a newly created object in PHP?

类似于:

class Foo {
    public function xyz() { ... return $this; }
}

$my_foo = new Foo()->xyz();

有人知道实现这一目标的方法吗?

Anyone know of a way to achieve this?

推荐答案

在 PHP 5.4+ 中，解析器已被修改，因此您可以执行类似的操作

In PHP 5.4+, the parser's been modified so you can do something like this

(new Foo())->xyz();

将实例化在括号中，并用链子连接起来.

Wrap the instantiation in parenthesis, and chain away.

在 PHP 5.4 之前，当您使用

Prior to PHP 5.4, when you're using the 

new Classname();

语法，您不能将方法调用链接到实例化之外.这是 PHP 5.3 语法的限制.一旦对象被实例化，您就可以将其链接起来.

syntax, you can't chain a method call off the instantiation. It's a limitation of PHP 5.3's syntax. Once an object is instantiated, you can chain away.

我见过用来解决这个问题的一种方法是某种静态实例化方法.

One method I've seen used to get around this is a static instantiation method of some kind. 

class Foo
{
    public function xyz()
    {
        echo "Called","
";
        return $this;
    }

    static public function instantiate()
    {
        return new self();
    }
}


$a = Foo::instantiate()->xyz();

通过在静态方法中包装对 new 的调用，您可以使用方法调用实例化一个类，然后您就可以自由地将其链接起来.

By wrapping the call to new in a static method, you can instantiate a class with method call, and you're then free to chain off that.

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