PHP released its new version on 26 November 2020. PHP which is a recursive acronym like GNU stands for PHP: Hypertext Preprocessor. It is one of the most used backend language in the field of web development. Although now new web development frameworks have arrived like NodeJS, Django, Flask, Laravel, Drupal, etc still PHP is a major player in the back-end market. PHP is a general-purpose scripting language especially suited to web development. It was originally created by Danish-Canadian programmer Rasmus Lerdorf in 1994.

The PHP development team stated about its new release as:

"PHP 8.0 is a major update of the PHP language.
It contains many new features and optimizations including named arguments, union types, attributes, constructor property promotion, match expression, nullsafe operator, JIT, and improvements in the type system, error handling, and consistency."

Some of the major changes in the new release are:-

• Named Arguments
• Attributes
• Constructor Property Promotion
• Union Types
• Match Expression
• Nullsafe Operator
• Consistent type errors for internal functions
• New JIT compilation engines

The details of some of these changes is given below

Named Arguments

Specify only required parameters, skipping optional ones.
Arguments are order-independent and self-documented.

// PHP 7
htmlspecialchars($string, ENT_COMPAT | ENT_HTML401, 'UTF-8', false);

// PHP 8
htmlspecialchars($string, double_encode: false);

Attributes

Instead of PHPDoc annotations, you can now use structured metadata with PHP's native syntax.

// PHP 7
class PostsController
{
    /**
     * @Route("/api/posts/{id}", methods={"GET"})
     */
    public function get($id) { /* ... */ }
}

// PHP 8
class PostsController
{
    #[Route("/api/posts/{id}", methods: ["GET"])]
    public function get($id) { /* ... */ }
}

Constructor property promotion

Less boilerplate code to define and initialize properties.

//PHP 7
class Point {
  public float $x;
  public float $y;
  public float $z;

  public function __construct(
    float $x = 0.0,
    float $y = 0.0,
    float $z = 0.0,
  ) {
    $this->x = $x;
    $this->y = $y;
    $this->z = $z;
  }
}

// PHP 8
class Point {
  public function __construct(
    public float $x = 0.0,
    public float $y = 0.0,
    public float $z = 0.0,
  ) {}
}

Union types

Instead of PHPDoc annotations for a combination of types, you can use native union type declarations that are validated at runtime.

//PHP 7
class Number {
  /** @var int|float */
  private $number;

  /**
   * @param float|int $number
   */
  public function __construct($number) {
    $this->number = $number;
  }
}

new Number('NaN'); // Ok

//PHP 8
class Number {
  public function __construct(
    private int|float $number
  ) {}
}

new Number('NaN'); // TypeError

Match Expression

The new match is similar to switch and has the following features:

• Match is an expression, meaning its result can be stored in a variable or returned.
• Match branches only support single-line expressions and do not need a break; statement.
• Match does strict comparisons.

// PHP 7
switch (8.0) {
  case '8.0':
    $result = "Oh no!";
    break;
  case 8.0:
    $result = "This is what I expected";
    break;
}
echo $result;
//> Oh no!

// PHP 8
echo match (8.0) {
  '8.0' => "Oh no!",
  8.0 => "This is what I expected",
};
//> This is what I expected

Nullsafe operator

Instead of null check conditions, you can now use a chain of calls with the new nullsafe operator. When the evaluation of one element in the chain fails, the execution of the entire chain aborts and the entire chain evaluates to null.

// PHP 7
$country =  null;

if ($session !== null) {
  $user = $session->user;

  if ($user !== null) {
    $address = $user->getAddress();

    if ($address !== null) {
      $country = $address->country;
    }
  }
}

//PHP 8
$country = $session?->user?->getAddress()?->country;

Saner string to number comparisons

When comparing to a numeric string, PHP 8 uses a number comparison. Otherwise, it converts the number to a string and uses a string comparison.

// PHP 7
0 == 'foobar' // true

// PHP 8
0 == 'foobar' // false

These are some of the changes to know about all the changes visit this link.