Named Arguments (PHP 8.0)

TL;DR

Explanation

named_arg: value syntax at call sites: array_slice($arr, offset: 1, length: 3). Benefits: skip optional params with defaults, document complex calls, reorder args. Works with built-in functions too: htmlspecialchars($str, ENT_QUOTES | ENT_SUBSTITUTE, encoding: 'UTF-8'). In attributes: #[Route(path: '/home', methods: ['GET'])]. Named args cannot be combined with positional args in PHP 8.0 (fixed in 8.1). Spreading named args: fn(...$named). Cannot use named args for constructors with property promotion before 8.1. Named args in array_slice removed need to pass all earlier args.

Common Misconception

Why It Matters

Common Mistakes

• Using named args for the first positional argument — only useful for optional params.
• Mixing positional and named args incorrectly (positional must come first).
• Not using named args in attributes where they dramatically improve readability.

Code Examples

array_slice($array, 1, 3, true); // What is true?
setcookie('session', $val, 0, '', '', true, true); // What are the booleans?

array_slice($array, offset: 1, length: 3, preserve_keys: true);

setcookie(
    name: 'session',
    value: $val,
    secure: true,
    httponly: true
);

References

• ↗ https://www.php.net/manual/en/functions.named-arguments.php

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