第2个打印结果为什么是888,还有(obj.inner.print=obj.inner.print)()这种写法没看懂?

var obj = {

    num:8,

    inner: {

        num: 6,

        print: function () {

            console.log(this.num);

        }

    }

}

num = 888;

obj.inner.print();

var fn = obj.inner.print;

fn();

(obj.inner.print)();

(obj.inner.print = obj.inner.print)();