iota.Ternary.scala Maven / Gradle / Ivy

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package iota

/**
  * @author pfnguyen
  */
private[iota] trait TernaryOps {
  /** create a K-combinator based on a ternary expression.
    *  for example: `condK(istrue ? (yes => IO[yes]) | (no => IO[no]))`
    */
  def condK[A](ternary: Ternary[A]): Kestrel[A] = ternary match {
    case TernaryCondition(b, ifTrue) => if (b)      ifTrue      else noopK[A]
    case TernaryElse(cond, ifFalse)  => if (cond.b) cond.ifTrue else ifFalse
  }
}

sealed trait Ternary[A]
private[iota] case class TernaryElse[A](cond: TernaryCondition[A], ifFalse: Kestrel[A]) extends Ternary[A]
case class TernaryCondition[A] private[iota](b: Boolean, ifTrue: Kestrel[A]) extends Ternary[A] {
  def |(ifFalse: Kestrel[A]): TernaryElse[A] = TernaryElse(this, ifFalse)
}