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Making call_user_func_array more readable

There’s a lot PHP 7 love going around these days, but PHP 5.6 has it’s fair share of nice features too. One of those features is the splat operator. It looks like this: ....

The splat operator can capture a variable number of arguments.

function logThis(...$messages)
{
    foreach ($messages as $message) {
        echo $message.PHP_EOL;
    }
}

logThis('one', 'two', 'three');

You can still use regular arguments as well:

function logThis($firstMessage, ...$otherMessages)
{
    echo "superimportant: {$firstMessage}".PHP_EOL;

    foreach ($otherMessages as $message) {
        echo $message.PHP_EOL;
    }
}

logThis('one', 'two', 'three');

Another usage for the splat operator is argument unpacking:

$messages[] = "one";
$messages[] = "two";
$messages[] = "three";

logThis(...$messages);

The operator can also help replacing usages of call_user_func_array to something more readable. Consider this contrived example where all calls to a class are forwarded to a dependency.

class ClassA
{
    protected $classB;

    public function __construct(ClassB $classB)
    {
        $this->classB = $classB;
    }

    public function __call($method, $args)
    {
        call_user_func_array([$this->classB, $method], $args);
    }
}

Using this splat operator this can be rewritten to:

class ClassA
{
    protected $classB;

    public function __construct(ClassB $classB)
    {
        $this->classB = $classB;
    }

    public function __call($method, $args)
    {
        $this->classB->$method(...$args);
    }
}

Do you know some other cool usage of the operator? Let me know in the comments below.

Freek Van der Herten is a partner and developer at Spatie, an Antwerp based company that specializes in creating web apps with Laravel. After hours he writes about modern PHP and Laravel on this blog. When not coding he’s probably rehearsing with his kraut rock band. He loves waffles and butterflies.