Key New Features in PHP 8: Named Parameters, Union Types, Match Expressions, and More

1. Named Parameters: Allows developers to pass arguments to functions by name instead of position, improving flexibility and readability.

function greet($name, $age) {
    echo "Hello $name, you are $age years old.";
}

greet(age: 25, name: "John");

2. Union Types: Enables specifying multiple possible types for function parameters, return types, etc., enhancing flexibility and reusability.

function foo(string|int $value): void {
    echo $value;
}

3. Match Expression: A more concise and expressive alternative to the switch statement for value matching.

$result = match($value) {
    1 => "One",
    2 => "Two",
    default => "Other",
};

4. Nullsafe Operator ( ?-> ): Simplifies accessing properties or methods on potentially null objects, reducing boilerplate null checks.

$length = $obj?->getProperty()?->getLength();

5. Attributes: A powerful tool for adding metadata to classes, methods, and functions, allowing behavior customization.

#[Route("/user/{id}")]
class UserController {
    #[HttpGet("/info")]
    public function getInfo($id) { }
}

6. Constructor Property Promotion: Concise syntax for declaring and initializing properties directly in the constructor signature.

class Person {
    public function __construct(
        public string $name,
        public int $age
    ) {}
}

7. WeakMap: A special map that allows objects to be used as keys without preventing their garbage collection, helping avoid memory leaks.

$map = new WeakMap();
$map[$obj] = "value";

8. Static Return Type: Allows a method to declare static as its return type, indicating it returns an instance of the called class.

class A {
    public static function getInstance(): static {
        return new static();
    }
}

9. Throw Expression: Enables throwing exceptions directly within expressions, useful in ternary operators.

$result = $value > 0 ? $value : throw new InvalidArgumentException("Invalid value");

10. Stringable Interface: By implementing Stringable , a class can define its own __toString() method for string conversion.

class MyClass implements Stringable {
    public function __toString(): string {
        return "MyClass";
    }
}

11. get_debug_type() Function: Returns a string with detailed type information of a variable, including the exact class name for objects.

$type = get_debug_type($var);

12. str_contains() Function: Checks whether a needle string exists within a haystack string, returning true or false.

if (str_contains($haystack, $needle)) {
    echo "Found";
}

13. str_starts_with() and str_ends_with() Functions: Determine if a string starts or ends with a given substring.

if (str_starts_with($string, $prefix)) {
    echo "Starts with prefix";
}

14. fdiv() Function: Performs floating‑point division and returns the result, handling special cases like NaN and infinities.

$result = fdiv(10.0, 3.0);

15. Error‑Suppression Operator ( @ ): Allows suppression of non‑exception errors such as warnings, enabling smoother execution of subsequent code.

$value = @some_function(); // Suppress errors