array-dic.php

<?php

class Foo {
    public $bar;

    function __construct($bar)
    {
        $this->bar = $bar;
    }
}

class Bar {}

function service($factory) {
    $value = null;
    return function () use (&$value, $factory) {
        return $value = $value ?: $factory();
    };
}

$dic = [
    'foo' => service(function () use (&$dic) {
        return new Foo($dic['bar']());
    }),
    'bar' => service(function () {
        return new Bar();
    }),
];

var_dump($dic['foo']()->bar);
var_dump($dic['foo']()->bar === $dic['bar']());