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

}


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';
    }
}

?>

add a note

BackedEnum 接口

简介

接口摘要

目录

User Contributed Notes 1 note