class person
{
  public function age(int $age) : string
  {
    return 'Age is ' . $age;
  }
}

use Publishers\Packt\{ Book, Ebook, Video};
use function Publishers\Packt\{ getBook, saveBook };
use const Publishers\Packt\{ COUNT, KEY };

use Publishers\Packt\{
  Book,
  Ebook,
  Video,
  function getBook,
  function saveBook,
  const COUNT,
  const KEY
};

use Publishers\Packt\{
  Paper\Book,
  Electronic\Ebook,
  Media\Video
};

new class(argument) { definition };

$name = new class('You') {
  public function __construct($name)
  {
    echo $name;
  }
};

class Packt
{
  protected $number;
  public function __construct()
  {
    echo 'parent construct';
  }
  public function getNumber() : float
  {
    return $this->number;
  }
}
$number = new class(5) extends Packt
{
  public function __construct(float $number)
  {
    parent::__construct();
    $this->number = $number;
  }
};
echo $number->getNumber();

interface Publishers
{
  public function __construct(string name, string address);
  public function getName();
  public function getAddress();
}
class packt
{
  protected $number;
  protected $name;
  protected $address;
  public function ...
}
$info = new class('name', 'address') extends Packt implement Publishers
{
  public function __construct(string $name, string $address)
  {
    $this->name = $name;
    $this->address = $address;
  }
  public function getName() : string
  {
    return $this->name;
  }
  public function getAddress() : string
  {
    return $this->address;
  }
}
echo $info->getName() . ' ' . $info->getAddress();

class Math
{
  public $first_number = 10;
  public $second_number = 10;
  public function add() : float
  {
    return $this->first_number + $this->second_number;
  }
  public function mutiply_sum()
  {
    return new class() extends Math
    {
      public function mutiply(float $third_number) : float
      {
        return $this->add() * $third_number;
      }
    };
  }
}
$math = new Math();
echo $math->mutiply_sum()->mutiply(2);

try
{
  ...
} catch(Error $e)
{
  echo $e->getMessage();
}

$title = $post['title'] ?? NULL;
$title = $post['title'] ?? $get['title'] ?? 'No title';

$first = ['name' => 'second'];
$second = 'two';
echo $$first['name'];
echo ${Sfirst['name']}; // PHP7
...
echo $object->$methods['title'];
echo $object->{$methods['title']}; // PHP7

const STORES = ['en', 'fr', 'ar']; // php5.6
define('STORES', ['en', 'fr', 'ar']); // php7

// php7之前
switch (true) {
  case 'value':
    # code...
    break;
  default:
    # code...
    break;
  default:
    # code...
    break;
}
// php7
switch (true) {
  case 'value':
    # code...
    break;
  default:
    # code...
    break;
}

session_start([
  'cookie_lifetime' => 3600,
  'read_and_close' => true
]);

$result = unserialize($object, ['allowed_classes' => ['Book', 'Ebook']]);