PHP 8.0.26 Released!

BackedEnum 接口

(PHP 8 >= 8.1.0)

简介

引擎会自动应用 BackedEnum 接口到回退枚举。 用户自定义类不能实现该接口。 由于引擎已提供枚举的默认实现,因此不能重载它的接口。 主要将它用于类型检测。

接口摘要

interface BackedEnum extends UnitEnum {
/* 方法 */
public static from(int|string $value): static
public static tryFrom(int|string $value): ?static
/* 继承的方法 */
public static UnitEnum::cases(): array
}

目录

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User Contributed Notes 1 note

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7
whatuwant
9 months ago
As of PHP 8.1, while `UnitEnum` & `BackedEnum` cannot be implemented by user-defined classes, it seems they can be extended by user-defined interfaces and eventually be implemented by enums.

<?php

interface TestEnumInterface extends \BackedEnum
{
    public function
foo(): string;
}

enum TestEnum: string implements TestEnumInterface
{
    case
CASE_1 = 'case 1';
    case
CASE_2 = 'case 2';

    public function
foo(): string
   
{
        return
'bar';
    }
}

?>
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