相关疑难解决方法(0)

此代码来自使用Scala的模式匹配查询数据集:

object & { def unapply[A](a: A) = Some((a, a)) }

"Julie" match {
  case Brothers(_) & Sisters(_) => "Julie has both brother(s) and sister(s)"
  case Siblings(_) => "Julie's siblings are all the same sex"
  case _ => "Julie has no siblings"
}

// => "Julie has both brother(s) and sister(s)"

&实际上如何运作？我没有在连词的任何地方看到布尔测试.这个Scala魔法是如何工作的？