Обектно ориентирано програмиране за отчаяни със Скала

Soooo.... last time?

Всичка са писали обектно...нали?

tl;dr

Накратко за nominal vs structured typing

Основи на ООП

ООП в Скала - Classes

class Animal

class Mammal(order: String) extends Animal {
  var milk: Boolean = true
  val theMilk: Boolean = true
  def zeMilk: Boolean = true
}

ООП в Скала - Companion objects

class Mammal(val order: String) extends Animal {
  private def milk: Boolean = true
}

object Mammal {
  private[companion] val RODENT = "rodentia"
  private[companion] val PRIMATE = "primates"

  def apply(): Mammal = new Mammal(RODENT)
  def apply(order: String): Mammal = new Mammal(order)

  def gotMilk(m:Mammal): Boolean = m.milk
}

ООП в Скала - Traits

trait Edible {
  def isPoisonous: Boolean
  def isDelicious: Boolean

  def ICanHazEat(): Boolean = !isPoisonous && isDelicious
}

class Mammal(
  val order: String,
  val isDelicious: Boolean = true,
  val isPoisonous: Boolean = false,
) extends Animal with Edible {
  private def milk: Boolean = true
}

ООП в Скала - Case classes

sealed trait Animal {
  val order: String
}

case class Mammal(
  order: String = "rodentia",
  milk: Boolean = true,
) extends Animal

Scala ООП в практиката

Next time....

References

• SICP - https://mitpress.mit.edu/sites/default/files/sicp/index.html
• Structural typing examples - https://blog.carbonfive.com/2012/09/23/structural-typing-compile-time-duck-typing/
• UAP - Just google it