Container Factory Composition

PSR11-Container-Get-Closure.php

<?php
//..
class Container implements ContainerInterface
{
    //..
    public function get($dependency)
    {
        if (!$this->has($dependency)) {
            throw new DependencyNotRegisteredException($dependency);
        }
        $entry = $this->instances[$dependency];

        if ($entry instanceof Closure) { // We use closures in order to enable factory composition
            return $entry($this);
        }
        return $this->concretize($entry);
    }
   //..
}