Chemaclass

<?php
class User {
    public int $id;
    public string $name;
}

Chemaclass

<?php
$factor = 10;
$nums = array_map(fn($n) => $n * $factor, [1, 2, 3, 4]);
// $nums = array(10, 20, 30, 40);

Chemaclass

<?php
class A {}
class B extends A {}

class Producer {
    public function method(): A {}
}
class ChildProducer extends Producer {
    public function method(): B {}
}

Chemaclass

<?php
$array['key'] ??= computeDefault();
// is roughly equivalent to
if (!isset($array['key'])) {
    $array['key'] = computeDefault();
}

Chemaclass

<?php
$parts = ['apple', 'pear'];
$fruits = ['banana', 'orange', ...$parts, 'watermelon'];
// ['banana', 'orange', 'apple', 'pear', 'watermelon'];

Chemaclass

<?php
$float = 6.674_083e-11; 
$decimal = 299_792_458;   
$hexadecimal = 0xCAFE_F00D;   
$binary = 0b0101_1111;  

Chemaclass

<?php
mb_strtoupper("Straße");
// Produces STRAßE on PHP 7.2
// Produces STRASSE on PHP 7.3

Chemaclass

<?php
mb_ereg('(?<word>\w+)', '国', $matches);
// => [0 => "国", 1 => "国", "word" => "国"];

Chemaclass

<?php
function test(object $obj) : object
{
    return new SplQueue();
}

test(new StdClass());

Chemaclass

<?php
abstract class A
{
    abstract function test(string $s);
}

abstract class B extends A
{
    // overridden - still maintaining contravariance 
    // for parameters and covariance for return