Scala example source code file (UnwriterTTest.scala)

This example Scala source code file (UnwriterTTest.scala) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Scala by Example" ^TM.

Learn more about this Scala project at its project page.

Java - Scala tags/keywords

apply, arbitrary, bind, equal, foldable, functor, speclite, traverse, unwriterarb, unwritertopt, unwriterttest

The UnwriterTTest.scala Scala example source code

package scalaz

import scalaz.scalacheck.ScalazProperties._
import scalaz.scalacheck.ScalazArbitrary._
import scalaz.scalacheck.ScalaCheckBinding._
import std.AllInstances._
import org.scalacheck.Arbitrary

object UnwriterTTest extends SpecLite {

  type UnwriterTOpt[W, A] = UnwriterT[Option, W, A]
  type UnwriterTOptInt[A] = UnwriterTOpt[Int, A]

  checkAll(equal.laws[UnwriterTOptInt[Int]])
  checkAll(bind.laws[UnwriterTOptInt])
  checkAll(traverse.laws[UnwriterTOptInt])
  checkAll(bitraverse.laws[UnwriterTOpt])

  implicit def UnwriterArb[F[_], W, A](implicit W: Arbitrary[W], A: Arbitrary[A]): Arbitrary[Unwriter[W, A]] =
    Applicative[Arbitrary].apply2(W, A)(Unwriter(_, _))

  checkAll(comonad.laws[Unwriter[Int, ?]])

  object instances {
    def equal[F[_], W, A](implicit E: Equal[F[(W, A)]]) = Equal[UnwriterT[F, W, A]]
    def functor[F[_]: Functor, W] = Functor[UnwriterT[F, W, ?]]
    def apply[F[_]: Apply, W] = Apply[UnwriterT[F, W, ?]]
    def bind[F[_]: Bind, W] = Bind[UnwriterT[F, W, ?]]
    def bifunctor[F[_]: Functor] = Bifunctor[UnwriterT[F, ?, ?]]
    def bitraverse[F[_]: Traverse] = Bitraverse[UnwriterT[F, ?, ?]]
    def foldable[F[_]: Foldable, W] = Foldable[UnwriterT[F, W, ?]]
    def traverse[F[_]: Traverse, W] = Traverse[UnwriterT[F, W, ?]]

    object Unwriter {
      def comonad[W] = Comonad[Unwriter[W, ?]]
    }
  }
}