Type hint array arguments in PHP 5.6 using variadic functions and argument unpacking.

00-type-hinted-array-arguments.php

<?php

$run = function (callable ...$callables) {
    foreach ($callables as $callable) {
        $callable();
    }
};

$callables = [
    function () { echo 'Hello '; },
    function () { echo 'World'; },
    function () { echo '!' . PHP_EOL; },
];

$run(...$callables);

$callables = [
    function () { echo 'Hello '; },
    'World!' . PHP_EOL,
];

$run(...$callables);

01-output.txt

~$ php docs/test.php 
Hello World!
PHP Catchable fatal error:  Argument 2 passed to {closure}() must be callable, string given

Limitations

• Array argument must be last in the method definition
• Can't do scalar type hinting in 5.6
• Raises an error, not a catchable exception (workaround is to throw an exception in the error handler)