$prototype = new Baobab\Canvas();

$prototype->init();

$canvas1 = clone $prototype;

$canvas1->rect(3,6,4,12);

$canvas1->draw();

$canvas2 = clone $prototype;

$canvas2->rect(3,6,4,12);

$canvas2->draw();

<?php

class Account{

    public $balance;

    function __construct($balance)

    {

        $this->balance = $balance;

    }

}

class Person{

    private $name;

    private $age;

    private $id;

    public $account;

    function __construct($name, $age, Account $account){

        $this->name = $name;

        $this->age = $age;

        $this->account = $account;

    }

    function setId($id){

        $this->id = $id;

    }

    function __clone()

    {

        $this->id = 0;
　　     //在复制对象属性时只复制引用，并不复制引用的对象。如果不希望对象属性在被复制后被共享，可以显式的在__clone()方法中复制指向的对象。

        $this->account = clone $this->account;

    }

}

$person1 = new Person('xiaoli', 11, new Account(100));

$person1->setId(111);

$person1->account->balance += 110;

//clone使用“值复制”方式新生成一个对象，是一种浅复制，可以保证所有基本数据类型的属性被完全复制。
$person2 = clone $person1; $person2->account->balance += 1; $person3 = $person1; 

//person1 和 person3是指向的同一个对象，person1和person2是两个不同的对象 
var_dump($person1); 
var_dump($person2);
var_dump($person3);