如何将 Scala 构造函数参数公开为公共成员? [英] How do I expose Scala constructor arguments as public members?

问题描述

看看这个例子:

class Point(x: Double, y: Double){
  override def toString = "x: " + x + ", y: " + y
  def +(sourcePoint: Point) : Point = {
    return new Point(x + sourcePoint.x, y + sourcePoint.y
  }
}

如您所见，我想在 Point 类上定义一个 + 运算符方法.但这行不通因为在那个方法中，x 和 y 不能在 sourcePoint 局部变量上访问，因为它们是私有的，所以我把例子改成了这个:

As you can see I want to define a + operator method on the Point class. But this won't work because in that method, x and y can't be accessed on the sourcePoint local variable since they are private, so I changed the example into this:

class Point(_x: Double, _y: Double){
  var x = _x
  var y = _y

  override def toString = "x: " + x + ", y: " + y
  def +(sourcePoint: Point) : Point = {
    return new Point(x + sourcePoint.x, y + sourcePoint.y)
  }
}

这显然有效，但是有没有更简单的方法来定义这些变量，而不是从 _x -> x 和 _y -> y 开始.

That obviously worked, however is there an easier way to define these variables instead of going from _x -> x and _y -> y.

感谢您的帮助和时间！:)

Thanks for help and time! :)

推荐答案

是的，有:

class Point(val x: Int, val y: Int)

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