wakeup.php

<?php


class User {

    protected $name;  
    protected $timeline = array();

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

    public function addTweet(Tweet $tweet)  
    {  
        $this->timeline[] = $tweet;  
    }

}

class Tweet {

    protected $id;  
    protected $text;  
    protected $read;

    public function __construct($id, $text)  
    {  
        $this->id = $id;  
        $this->text = $text;  
        $this->read = false;  
    }

    public function __invoke($user)  
    {  
        $user->addTweet($this);  
        return $user;  
    }

}

$users = array(new User('Ev'), new User('Jack'), new User('Biz'));  
$tweet = new Tweet(123, 'Hello world');  
$users = array_map($tweet, $users);

var_dump($users);