What is the essence of the design and how is this possible?

Question

PHP

Good afternoon. Absolutely stupid question, but not out of my head.
I am picking the source code of Slim Framework. Found the design:

$this->container = new \Slim\Helper\Set();
$this->container['settings'] = array_merge(static::getDefaultSettings(), $userSettings);

How can you assign an object to a class member, and then work with it as an array? There are no magic methods in \Slim\Helper\Set. Shed some light on the situation, please. Thanks in advance.

Answer 1

class Set implements \ArrayAccess, \Countable, \IteratorAggregate

The point is that this class implements the ArrayAccess interface .
PS
Also available - https://github.com/slimphp/Slim/blob/2.x/Slim/Help...