PHP将类添加到另一个类

我想用

start

启动订阅，如果

addTrail

当前存在，请更改

start

的结果

无试用期开始订阅

 (new Premium)->start(1, 'paid', 30);

 (new Premium)->start(1, 'paid', 30)->addTrial(15);

在15天试用期内开始订阅

 (new Premium)->start(1, 'paid', 30);

 (new Premium)->start(1, 'paid', 30)->addTrial(15);

说明

class Premium
{
    private $trialDays;

    public function start($user_id, $type, $endsInDays) {

        if($trialDays) {
            $endsInDays = $endsInDays + $trialDays;
        }

        return 'Your subscription will end in ' . $endsInDays . 'days';

    }

    public function addTrial($days) {
        $this->trialDays = $days;
    }

}

---

启动函数必须

返回$this如果要“链接”方法

否则，请使用标准语法

$premium = new Premium;
$premium->start(1,'paid',30);
$premium->addTrial(15);

这回答了你的问题吗？