为PHP 7中的属性键入提示吗? [英] Type hinting for properties in PHP 7?

问题描述

php 7是否支持类属性的类型提示?

Does php 7 support type hinting for class properties?

我的意思是，不仅是针对设置者/获取者" ，而且还针对财产本身.

I mean, not just for setters/getters but for the property itself.

类似的东西:

class Foo {
    /**
     *
     * @var Bar
     */
    public $bar : Bar;
}

$fooInstance = new Foo();
$fooInstance->bar = new NotBar(); //Error

推荐答案

PHP 7.4 将支持类型化属性像这样:

PHP 7.4 will support typed properties like so:

class Person
{
    public string $name;
    public DateTimeImmutable $dateOfBirth;
}

---

PHP 7.3和更早版本不支持此功能，但是有一些替代方法.

---

PHP 7.3 and earlier do not support this, but there are some alternatives.

您可以创建一个私有属性，该私有属性只能通过具有类型声明的getter和setter进行访问:

You can make a private property which is accessible only through getters and setters which have type declarations:

class Person
{
    private $name;
    public function getName(): string {
        return $this->name;
    }
    public function setName(string $newName) {
        $this->name = $newName;
    }
}

您还可以设置公共属性，并使用docblock向阅读代码和使用IDE的人员提供类型信息，但这不提供运行时类型检查:

You can also make a public property and use a docblock to provide type information to people reading the code and using an IDE, but this provides no runtime type-checking:

class Person
{
    /**
      * @var string
      */
    public $name;
}

实际上，您可以将getter和setter以及一个文档块结合在一起.

And indeed, you can combine getters and setters and a docblock.

如果您更喜欢冒险，可以使用 __get，__set，__isset和__unset魔术方法，然后自己检查类型.不过，我不确定是否会推荐.

If you're more adventurous, you could make a fake property with the __get, __set, __isset and __unset magic methods, and check the types yourself. I'm not sure if I'd recommend it, though.

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