June 2018 Update

Task/Polymorphic-copy/Elena/polymorphic-copy.elena

@@ -0,0 +1,24 @@
+import extensions.
+
+class T
+{
+    Name = "T".
+
+    clone = T new.
+}
+
+class S :: T
+{
+    Name = "S".
+
+    clone = S new.
+}
+
+program =
+[
+    type<T> original := S new.
+    type<T> clone := original clone.
+
+    console printLine(original Name).
+    console printLine(clone Name).
+].

Task/Polymorphic-copy/Scala/polymorphic-copy.scala

@@ -0,0 +1,21 @@
+object PolymorphicCopy {
+
+  def main(args: Array[String]) {
+    val a: Animal = Dog("Rover", 3, "Terrier")
+    val b: Animal = a.copy() // calls Dog.copy() because runtime type of 'a' is Dog
+    println(s"Dog 'a' = $a") // implicitly calls Dog.toString()
+    println(s"Dog 'b' = $b") // ditto
+    println(s"Dog 'a' is ${if (a == b) "" else "not"} the same object as Dog 'b'")
+  }
+
+  case class Animal(name: String, age: Int) {
+
+    override def toString = s"Name: $name, Age: $age"
+  }
+
+  case class Dog(override val name: String, override val age: Int, breed: String) extends Animal(name, age) {
+
+    override def toString = super.toString() + s", Breed: $breed"
+  }
+
+}