View difference between Paste ID: JMFaVnjv and 66rgvt9d

 // ---------Framework:---------
 
 abstract class Engine {
-	abstract type MixIn
+	class Base(val children: Seq[Base])
-	// add members to this base class which are defined only in the subclass
+
-	class Base(val children: Seq[Base]) extends MixIn
+
 	final class Spec1(val foo: String, children: Seq[Base]) extends Base(children)
 	final class Spec2(val bar: String, children: Seq[Base]) extends Base(children)
 }
 
 object Engine {
 	def runExample(engine: Engine) {
 		val spec1 = new engine.Spec1("foo", Seq.empty)
 		engine.doSomething(spec1)
 		val spec2 = new engine.Spec2("foo", Seq(new Spec1("foo", Seq.empty)))
 		engine.doSomething(spec2)
 	}
 }
 
 // ---------Client:---------
 
 class ConcreteEngine {
 	override class Base(val children: Seq[Base]) {
 		val height = if(children.isEmpty()) 0 else children.map{_.height}.max
-	trait Height {
+
 	override def doSomething(base: Base) {
 		println("Node @ " + base.height)
-	override type MixIn = Height
+
 }
 
 object Main extends App {
 	Engine.run(new ConcreteEngine())
 }