traits.scala #daimonscala 21

gistfile1.scala

type HasName = { def name: String }

trait CanSpeak { this: HasName =>
  def introduce = println("Hi, I'm " + name + ".")
}

trait CanRun { this: HasName =>
  def run = println(name + " start running!")
}

trait CanEat { this: HasName =>
  def eat = println(name + " start eating!")
}

case class Person(name : String)

val andy = new Person("Andy") with CanSpeak with CanRun with CanEat
andy.introduce
andy.run
andy.eat


trait YetAnotherRun {
  def run = println("Run!" * 3)
}

val forrest = new Person("Forrest") with YetAnotherRun
forrest.run

/*
scala> val forrest = new Person("Forrest") with CanRun with YetAnotherRun
<console>:12: error: overriding method run in trait CanRun of type => Unit;
 method run in trait YetAnotherRun of type => Unit needs `override' modifier
       val forrest = new Person("Forrest") with CanRun with YetAnotherRun
                         ^
 */