Example code for Lambda Jam Category Theory exercises

Classes.scala

package cat

object Classes {

  // Convenient subtype syntax: Banana < Fruit
  implicit class ClassOps(thisClass: Class[_]) {
    def <:<(other: Class[_]): Boolean = 
      other isAssignableFrom thisClass
  }

  val Food = classOf[Food]
  val Fruit = classOf[Fruit]
  val Banana = classOf[Banana]
  val Cumquat = classOf[Banana]
  val Grape = classOf[Grape]
  val Meat = classOf[Meat]
  val Yak = classOf[Yak]
  val Goat = classOf[Goat]
  val Kangaroo = classOf[Kangaroo]
  val Tool = classOf[Tool]
  val Spanner = classOf[Spanner] 
  val Hammer = classOf[Hammer]
}

trait Food

trait Fruit extends Food
class Banana extends Fruit
class Cumquat extends Fruit
class Grape extends Fruit

trait Meat extends Food
class Yak extends Meat
class Goat extends Meat
class Kangaroo extends Meat


trait Tool
class Spanner extends Tool
class Hammer extends Tool