PHP Callback which doesn't take a method as an argument
<p>I want to set a callback that simply creates an instance of a class and implements the default constructor. How do I do this?</p>

<p>I know you create an array if you want to call a method of a class after it is instantiated, such as <code>array(new Order(), "runOrder")</code>, but I don't want to pass a second argument (method name), as the constructor handles this.</p>
