Question

For years I’ve been biting bullets attempting to write functional code in PHP with hacks like this:

class Foo {
    function addOne($wu) {
        return $wu + 1;
    }
    function getBiggerThings(array $things) {
        $that = $this;
        return array_map(function ($i) use ($that) {
            return $that->addOne($i);
        }, $things); 
}

Today a colleague pointed out that I could write:

return array_map(array($this, 'addOne'), $things);

I can’t find any documentation on this on php.net. Am I reading the callback type documentation incorrectly?

Answer 1

I’d like to highlight the following from commented PHP docs:

A method of an instantiated object is passed as an array containing an object at index 0 and the method name at index 1.

This actually is since a pretty long time, so to say before PHP 5.3 which allowed you the anonymous function “workaround”.