PHP: BackedEnum - Manual
The BackedEnum interface
(PHP 8 >= 8.1.0)
Introduction
The BackedEnum interface is automatically applied to backed enumerations by the engine. It may not be implemented by user-defined classes. Enumerations may not override its methods, as default implementations are provided by the engine. It is available only for type checks.
Table of Contents
- BackedEnum::from — Maps a scalar to an enum instance
- BackedEnum::tryFrom — Maps a scalar to an enum instance or null
Found A Problem?
4 years 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';
}
}
?>