YAPC::EU 2018 Glasgow Update!

Task/Polymorphism/Scala/polymorphism.scala

@@ -0,0 +1,36 @@
+object PointCircle extends App {
+
+  class Point(x: Int = 0, y: Int = 0) {
+
+    def copy(x: Int = this.x, y: Int = this.y): Point = new Point(x, y)
+
+    override def toString = s"Point x: $x,  y: $y"
+  }
+
+  object Point {
+    def apply(x: Int = 0, y: Int = 0): Point = new Point(x, y)
+  }
+
+  case class Circle(x: Int = 0, y: Int = 0, r: Int = 0) extends Point(x, y) {
+
+    def copy(r: Int): Circle = Circle(x, y, r)
+
+    override def toString = s"Circle x: $x,  y: $y,  r: $r"
+  }
+
+  val p = Point()
+  val c = Circle()
+  println("Instantiated ", p)
+  println("Instantiated ", c)
+
+  val q = Point(5, 6)
+  println("Instantiated ", q)
+  val r = q.copy(y = 7) // change y coordinate
+  println(r, " changed y coordinate")
+
+  val d = Circle(5, 6, 7)
+  println("Instantiated ", d)
+  val e = d.copy(r = 8) // change radius
+  println(e, " changed radius")
+
+}