Clojure style function...

FunctionTest.scala

object Test1 {
  val fib: Any => Stream[Int] = {
    case () => fib(1)
    case (a: Int) => fib(0, a) 
    case (a: Int, b: Int) => Stream.cons(a, fib(b, a+ b))
  }
  
  val greet: Any => Unit = {
    case () => println("Hello, world.")
    case (name: String) => println("Hello, " + name + ".")
  }
}

class Test2 {
  val fib: Any => Stream[Int] = {
    case () => fib(1)
    case (a: Int) => fib(0, a) 
    case (a: Int, b: Int) => Stream.cons(a, fib(b, a+ b))
  }
}

object FunctionTest extends App {
  println(Test1.fib().take(10).toList)
  Test1.greet()
  Test1.greet("Bob")
  println(new Test2().fib().take(10).toList)
}