Algebraic Data Types

adt.scala

sealed trait Food  {
  val calories:Double
}

case class Pizza(calories: Double, crust: String) extends Food
case class Hamburger(calories: Double, cheese:Boolean) extends Food

sealed trait Person  {
  val name:String
}

case class Student(name: String) extends Person
case class Programmer(name: String) extends Person

def printDetails(person: Person, food: Food) = {
  print(s" Hello ${person.name}, your food has ${food.calories} calories.")
}

printDetails(Student("Rob"), Pizza(1000, "thin")) // Hello Rob, your food has 1000 calories.