小编tom*_*tom的帖子

我有一组像这样的案例类

abstract class Shape  
case class Rectangle(width: Int, height: Int) extends Shape  
case class Location(x: Int, y: Int, shape: Shape) extends Shape  
case class Circle(radius: Int) extends Shape  
case class Group(shape: Shape*) extends Shape

其中基本上Group是一个形状数组.我需要定义一个大小方法来计算矩形,圆形和位置的大小,它直接只返回一个.但我对集团有困难.

object size extends Shape{  
  def size(s: Any) : Int = s match {  
    case Rectangle(x,y) => 1  
    case Group  // how to do it? Also having case Group(shape : Shape*) gives an error  
    case Circle(r) => 1    
    case Location(x,y,shape) => 1   
  }  
}  

我知道对于Group我需要使用map并向左折叠,但我真的无法为它创建逻辑.谢谢