8 つのコード ブロックで構成される PHP 8.1

enum Status
{
    case draft;
    case published;
    case archived;
    
    public function color(): string
    {
        return match($this) 
        {
            Status::draft => 'grey',   
            Status::published => 'green',   
            Status::archived => 'red',   
        };
    }
}

列挙型

---

class PostData
{
    public function __construct(
        public readonly string $title,
        public readonly string $author,
        public readonly string $body,
        public readonly DateTimeImmutable $createdAt,
        public readonly PostState $state,
    ) {}
}

読み取り専用プロパティ

---

class PostStateMachine
{
    public function __construct(
        private State $state = new Draft(),
    ) {
    }
}

イニシャライザの新機能

---

$fiber = new Fiber(function (): void {
    $valueAfterResuming = Fiber::suspend('after suspending');
    
    
});
 
$valueAfterSuspending = $fiber->start();
 
$fiber->resume('after resuming');

繊維、別名「緑色の糸」

$array1 = ("a" => 1);

$array2 = ("b" => 2);

$array = ("a" => 0, ...$array1, ...$array2);

var_dump($array); 

配列のアンパックは文字列キーもサポートします

---

function foo(int $a, int $b) {  }

$foo = foo(...);

$foo(a: 1, b: 2);

ファーストクラスの呼び出し可能オブジェクト

---

function generateSlug(HasTitle&HasId $post) {
    return strtolower($post->getTitle()) . $post->getId();
}

純粋な交差タイプ

---

$list = ("a", "b", "c");

array_is_list($list); 

$notAList = (1 => "a", 2 => "b", 3 => "c");

array_is_list($notAList); 

$alsoNotAList = ("a" => "a", "b" => "b", "c" => "c");

array_is_list($alsoNotAList); 

新しい array_is_list 関数