Traits can also extend each other. Have a look at the following example:
trait Ping { def ping(): Unit = { System.out.println("ping") }}trait Pong { def pong(): Unit = { System.out.println("pong") }}trait PingPong extends Ping with Pong { def pingPong(): Unit = { ping() pong() }}object Runner extends PingPong { def main(args: Array[String]): Unit = { pingPong() }}
The preceding example is simple and it should really just make the Runner object mix the two traits separately. Extending traits is useful in a design pattern called Stackable Traits, which we will be looking into later in this book.
