如何调用类的可调用属性

this->property() ?

<?php

class A
{
    public function __invoke($t)
    {
        return $t * 3;
    }
}


class B
{
    public function __construct(A $a)
    {
        $this->a = $a;
    }

    public function yo($t)
    {
        return $this->a($t);
    }
}

echo (new B(new A))->yo(8);

这将导致错误:

<br />
<b>Fatal error</b>:  Uncaught Error: Call to undefined method B::a() in [...][...]:21
Stack trace:
#0 [...][...](28): B-&gt;yo(8)
#1 {main}
  thrown in <b>[...][...]</b> on line <b>21</b><br />

为了使这项工作成功,我不得不改变方法 yo 具体如下:

public function yo($t)
{
    return ($this->a)($t); // this works
    $x = $this->a; // this works
    return $x($t); // as well
}