haphpiness

Anonymous Classes

PHP 7.0 added anonymous classes — inline, disposable class definitions. They're perfect for one-off implementations, testing, and anywhere you'd create a class that's only used once.

// Perfect for tests — no need to create a file for a stub
$logger = new class implements LoggerInterface {
    public array $logs = [];

    public function log($level, $message, array $context = []): void {
        $this->logs[] = compact('level', 'message', 'context');
    }
    // ... other PSR-3 methods
};

$service = new MyService($logger);
$service->doWork();
$this->assertCount(3, $logger->logs);

// Inline adapters
function createCacheAdapter(array &$store): CacheInterface {
    return new class($store) implements CacheInterface {
        public function __construct(private array &$store) {}

        public function get(string $key, mixed $default = null): mixed {
            return $this->store[$key] ?? $default;
        }

        public function set(string $key, mixed $value, int $ttl = 0): bool {
            $this->store[$key] = $value;
            return true;
        }
    };
}

// They support everything normal classes do:
// constructors, interfaces, traits, inheritance, properties
$event = new class('click', ['x' => 100]) extends Event implements Serializable {
    use HasMetadata;
    public function __construct(public string $type, public array $data) {
        parent::__construct();
    }
};

Anonymous classes reduce file proliferation. Instead of creating StubLogger.php for a single test, you define it inline where it's used. The class exists only in the scope where it's created — no namespace pollution, no autoloading overhead.