PHP 8.0 Highlights

AZPHP November 2020

Ian Littman / @iansltx

follow along at https://ian.im/php8az

Union Types

function query(
    PDO|PDOInterface $db, // same syntax as multi-catch
    string $query,
    ?array $params = []
): array|int {
    // do stuff
}

Stringable interface

function query(
    PDO|PDOInterface $db,
    string|Stringable $query, // anything with __toString()
    ?array $params = []
): array|int {
    // do stuff
}

Mixed Typehint

interface DoesAThing {
    function doAThing(mixed $thisCouldBeAnything): mixed;

# string|int|float|bool|null|array|object|callable|resource
}

Named parameters

query(query: 'SELECT 1', db: $pdo);

query(
    $pdo,
    params: ['one', 'two'],
    query: 'SELECT * FROM notes WHERE slug IN (?, ?)'
);

If you're writing a library, you have a whole new class of BC breaks to think about.

NullSafe Operator

interface NoteRepo {
    public function findBySlug(string $slug): ?Note;
}
class Note   { public Author $author; }
class Author { public string $name; }

$notes->findBySlug('nonexistent')?->author->name; // ?string

Match Expressions

switch (getRoute()) {
    case '/home':
    case '/':
        $title = 'Home Page';
        break;
    case '/profile':
        $title = getUserName();
        break;
    default:
        $title = 'My Great App!';
}

$title = match (getRoute()) {
    '/home', '/' => 'Home Page',
    '/profile' => getUserName(),
    default => 'My Great App!'
};

Class Constructor Property Promotion

class DbColumn
{
    public function __construct(
        private string $name,
        private bool $nullable = false
    ) {
        echo $this->name . ' is '
            . ($nullable ? '' : 'not ')
            . "nullable\n";
    }
}

Attributes

#[Attribute]

class DbColumn {
    public function __construct(
        private string $name,
        private bool $nullable = false
    ) {}
}

class Note {
    #[DbColumn('name')]
    public string $name;
}

$dbColumn = (new ReflectionClass('Note'))
    ->getProperties()[0] // $name property
    ->getAttributes()[0] // DbColumn ReflectionAttribute
    ->newInstance(); // DbColumn object with properties set

Catches with no exception variable

try {
    $api = API::connect();
    // do stuff with $api
} catch (BadApiKey) {
    // The type of the exception is enough to decide what
    // to do here, so we don't need the exception itself.
}

New functions | Methods!

• fdiv() - float division with INF/-INF returned for division by 0
• get_debug_type() - more accurate gettype() (names match typehints)
• str_contains(), str_starts_with(), str_ends_with() - returns booleans (vs. strpos)
• preg_last_error_msg() - friendlier message on why your regex match failed
• get_resource_id() - (int) $resource with type safety
• DateTime|DateTimeImmutable::createFromInterface()

• ian.im/php8az - these slides
• twitter.com/iansltx - me, online

Thanks! Questions?