PHP 8.1 in 8 code blocks

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

Enums

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,
    ) {}
}

Readonly properties

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

New in initializers

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

Fibers, a.k.a. "green threads"

Opinion-driven design

$array1 = ["a" => 1];

$array2 = ["b" => 2];

$array = ["a" => 0, ...$array1, ...$array2];

var_dump($array); // ["a" => 1, "b" => 2]

Array unpacking also supports string keys

function foo(int $a, int $b) { /* … */ }

$foo = foo(...);

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

First class callables

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

Pure intersection types

$list = ["a", "b", "c"];

array_is_list($list); // true

$notAList = [1 => "a", 2 => "b", 3 => "c"];

array_is_list($notAList); // false

$alsoNotAList = ["a" => "a", "b" => "b", "c" => "c"];

array_is_list($alsoNotAList); // false

The new array_is_list function