Merge pull request #1402 from pepegar/more-instances-for-prod

More instances for prod
typelevel · Oct 25, 2016 · 5c00fdf · 5c00fdf
2 parents c56fbab + 867b2a2
commit 5c00fdf
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diff --git a/core/src/main/scala/cats/data/Prod.scala b/core/src/main/scala/cats/data/Prod.scala
@@ -2,6 +2,7 @@ package cats
 package data
 
 import cats.functor.Contravariant
+import cats.syntax.cartesian._
 
 /**
  * [[Prod]] is a product to two independent functor values.
@@ -13,54 +14,74 @@ final case class Prod[F[_], G[_], A](first: F[A], second: G[A])
 object Prod extends ProdInstances
 
 private[data] sealed abstract class ProdInstances extends ProdInstances0 {
+  implicit def catsDataMonadCombineForProd[F[_], G[_]](implicit FF: MonadCombine[F], GF: MonadCombine[G]): MonadCombine[λ[α => Prod[F, G, α]]] = new ProdMonadCombine[F, G] {
+    def F: MonadCombine[F] = FF
+    def G: MonadCombine[G] = GF
+  }
+  implicit def catsDataOrderForProd[F[_], G[_], A](implicit FF: Order[F[A]], GF: Order[G[A]]): Order[Prod[F, G, A]] = new ProdOrder[F, G, A] {
+    def F: Order[F[A]] = FF
+    def G: Order[G[A]] = GF
+  }
+  implicit def catsDataShowForProd[F[_], G[_], A](implicit FF: Show[F[A]], GF: Show[G[A]]): Show[Prod[F, G, A]] = new ProdShow[F, G, A] {
+    def F: Show[F[A]] = FF
+    def G: Show[G[A]] = GF
+  }
+  implicit def catsDataContravariantForProd[F[_], G[_]](implicit FC: Contravariant[F], GC: Contravariant[G]): Contravariant[λ[α => Prod[F, G, α]]] = new ProdContravariant[F, G] {
+    def F: Contravariant[F] = FC
+    def G: Contravariant[G] = GC
+  }
+}
+
+private[data] sealed abstract class ProdInstances0 extends ProdInstances1 {
+  implicit def catsDataTraverseForProd[F[_], G[_]](implicit FF: Traverse[F], GF: Traverse[G]): Traverse[λ[α => Prod[F, G, α]]] = new ProdTraverse[F, G] {
+    def F: Traverse[F] = FF
+    def G: Traverse[G] = GF
+  }
   implicit def catsDataAlternativeForProd[F[_], G[_]](implicit FF: Alternative[F], GG: Alternative[G]): Alternative[λ[α => Prod[F, G, α]]] = new ProdAlternative[F, G] {
     def F: Alternative[F] = FF
     def G: Alternative[G] = GG
   }
-
+  implicit def catsDataMonadForProd[F[_], G[_]](implicit FM: Monad[F], GM: Monad[G]): Monad[λ[α => Prod[F, G, α]]] = new ProdMonad[F, G] {
+    def F: Monad[F] = FM
+    def G: Monad[G] = GM
+  }
   implicit def catsDataEqForProd[F[_], G[_], A](implicit FF: Eq[F[A]], GG: Eq[G[A]]): Eq[Prod[F, G, A]] = new Eq[Prod[F, G, A]] {
     def eqv(x: Prod[F, G, A], y: Prod[F, G, A]): Boolean =
       FF.eqv(x.first, y.first) && GG.eqv(x.second, y.second)
   }
 }
 
-private[data] sealed abstract class ProdInstances0 extends ProdInstances1 {
+private[data] sealed abstract class ProdInstances1 extends ProdInstances2 {
+  implicit def catsDataFoldableForProd[F[_], G[_]](implicit FF: Foldable[F], GF: Foldable[G]): Foldable[λ[α => Prod[F, G, α]]] = new ProdFoldable[F, G] {
+    def F: Foldable[F] = FF
+    def G: Foldable[G] = GF
+  }
   implicit def catsDataMonoidKForProd[F[_], G[_]](implicit FF: MonoidK[F], GG: MonoidK[G]): MonoidK[λ[α => Prod[F, G, α]]] = new ProdMonoidK[F, G] {
     def F: MonoidK[F] = FF
     def G: MonoidK[G] = GG
   }
-}
-
-private[data] sealed abstract class ProdInstances1 extends ProdInstances2 {
-  implicit def catsDataSemigroupKForProd[F[_], G[_]](implicit FF: SemigroupK[F], GG: SemigroupK[G]): SemigroupK[λ[α => Prod[F, G, α]]] = new ProdSemigroupK[F, G] {
-    def F: SemigroupK[F] = FF
-    def G: SemigroupK[G] = GG
-  }
-}
-
-private[data] sealed abstract class ProdInstances2 extends ProdInstances3 {
   implicit def catsDataApplicativeForProd[F[_], G[_]](implicit FF: Applicative[F], GG: Applicative[G]): Applicative[λ[α => Prod[F, G, α]]] = new ProdApplicative[F, G] {
     def F: Applicative[F] = FF
     def G: Applicative[G] = GG
   }
 }
 
-private[data] sealed abstract class ProdInstances3 extends ProdInstances4 {
+private[data] sealed abstract class ProdInstances2 extends ProdInstances3 {
+  implicit def catsDataSemigroupKForProd[F[_], G[_]](implicit FF: SemigroupK[F], GG: SemigroupK[G]): SemigroupK[λ[α => Prod[F, G, α]]] = new ProdSemigroupK[F, G] {
+    def F: SemigroupK[F] = FF
+    def G: SemigroupK[G] = GG
+  }
   implicit def catsDataApplyForProd[F[_], G[_]](implicit FF: Apply[F], GG: Apply[G]): Apply[λ[α => Prod[F, G, α]]] = new ProdApply[F, G] {
     def F: Apply[F] = FF
     def G: Apply[G] = GG
   }
 }
 
-private[data] sealed abstract class ProdInstances4 {
+private[data] sealed abstract class ProdInstances3 {
   implicit def catsDataFunctorForProd[F[_], G[_]](implicit FF: Functor[F], GG: Functor[G]): Functor[λ[α => Prod[F, G, α]]] = new ProdFunctor[F, G] {
     def F: Functor[F] = FF
     def G: Functor[G] = GG
   }
-  implicit def catsDataContravariantForProd[F[_], G[_]](implicit FC: Contravariant[F], GC: Contravariant[G]): Contravariant[λ[α => Prod[F, G, α]]] = new ProdContravariant[F, G] {
-    def F: Contravariant[F] = FC
-    def G: Contravariant[G] = GC
-  }
 }
 
 sealed trait ProdFunctor[F[_], G[_]] extends Functor[λ[α => Prod[F, G, α]]] {
@@ -78,7 +99,7 @@ sealed trait ProdContravariant[F[_], G[_]] extends Contravariant[λ[α => Prod[F
 sealed trait ProdApply[F[_], G[_]] extends Apply[λ[α => Prod[F, G, α]]] with ProdFunctor[F, G] {
   def F: Apply[F]
   def G: Apply[G]
-  def ap[A, B](f: Prod[F, G, A => B])(fa: Prod[F, G, A]): Prod[F, G, B] =
+  override def ap[A, B](f: Prod[F, G, A => B])(fa: Prod[F, G, A]): Prod[F, G, B] =
     Prod(F.ap(f.first)(fa.first), G.ap(f.second)(fa.second))
   override def product[A, B](fa: Prod[F, G, A], fb: Prod[F, G, B]): Prod[F, G, (A, B)] =
     Prod(F.product(fa.first, fb.first), G.product(fa.second, fb.second))
@@ -109,3 +130,56 @@ sealed trait ProdAlternative[F[_], G[_]] extends Alternative[λ[α => Prod[F, G,
   def F: Alternative[F]
   def G: Alternative[G]
 }
+
+sealed trait ProdMonad[F[_], G[_]] extends Monad[λ[α => Prod[F, G, α]]] with ProdApplicative[F, G] {
+  def F: Monad[F]
+  def G: Monad[G]
+  override def pure[A](a: A): Prod[F, G, A] =
+    Prod(F.pure(a), G.pure(a))
+
+  override def flatMap[A, B](p: Prod[F, G, A])(f: A => Prod[F, G, B]): Prod[F, G, B] =
+    Prod(F.flatMap(p.first)(f(_).first), G.flatMap(p.second)(f(_).second))
+
+  def tailRecM[A, B](a: A)(f: A => Prod[F, G, Either[A, B]]): Prod[F, G, B] =
+    Prod(F.tailRecM(a)(f(_).first), G.tailRecM(a)(f(_).second))
+}
+
+sealed trait ProdFoldable[F[_], G[_]] extends Foldable[λ[α => Prod[F, G, α]]] {
+  def F: Foldable[F]
+  def G: Foldable[G]
+
+  override def foldLeft[A, B](fa: Prod[F, G, A], b: B)(f: (B, A) => B): B =
+    G.foldLeft(fa.second, F.foldLeft(fa.first, b)(f))(f)
+
+  override def foldRight[A, B](fa: Prod[F, G, A], lb: Eval[B])(f: (A, Eval[B]) => Eval[B]): Eval[B] =
+    F.foldRight(fa.first, G.foldRight(fa.second, lb)(f))(f)
+}
+
+sealed trait ProdTraverse[F[_], G[_]] extends Traverse[λ[α => Prod[F, G, α]]] with ProdFoldable[F, G] {
+  def F: Traverse[F]
+  def G: Traverse[G]
+
+  override def traverse[H[_]: Applicative, A, B](fa: Prod[F, G, A])(f: A => H[B]): H[Prod[F, G, B]] =
+    (F.traverse(fa.first)(f) |@| G.traverse(fa.second)(f)).map(Prod(_, _))
+}
+
+sealed trait ProdMonadCombine[F[_], G[_]] extends MonadCombine[λ[α => Prod[F, G, α]]]
+  with ProdMonad[F, G] with ProdAlternative[F, G] {
+  def F: MonadCombine[F]
+  def G: MonadCombine[G]
+}
+
+sealed trait ProdShow[F[_], G[_], A] extends Show[Prod[F, G, A]] {
+  def F: Show[F[A]]
+  def G: Show[G[A]]
+
+  def show(prod: Prod[F, G, A]): String = s"Prod(${F.show(prod.first)}, ${G.show(prod.second)})"
+}
+
+sealed trait ProdOrder[F[_], G[_], A] extends Order[Prod[F, G, A]] {
+  def F: Order[F[A]]
+  def G: Order[G[A]]
+
+  def compare(x: Prod[F, G, A], y: Prod[F, G, A]): Int =
+    Array(F.compare(x.first, y.first), G.compare(x.second, y.second)).find(_ != 0).getOrElse(0)
+}
diff --git a/laws/src/main/scala/cats/laws/discipline/Arbitrary.scala b/laws/src/main/scala/cats/laws/discipline/Arbitrary.scala
@@ -130,6 +130,9 @@ object arbitrary extends ArbitraryInstances0 {
   implicit def catsLawsCogenForCoproduct[F[_], G[_], A](implicit F: Cogen[F[A]], G: Cogen[G[A]]): Cogen[Coproduct[F, G, A]] =
     Cogen((seed, x) => x.run.fold(F.perturb(seed, _), G.perturb(seed, _)))
 
+  implicit def catLawsCogenForProd[F[_], G[_], A](implicit F: Cogen[F[A]], G: Cogen[G[A]]): Cogen[Prod[F, G, A]] =
+    Cogen((seed, t) => F.perturb(G.perturb(seed, t.second), t.first))
+
   implicit def catsLawsArbitraryForShow[A: Arbitrary]: Arbitrary[Show[A]] =
     Arbitrary(Show.fromToString[A])
 

diff --git a/tests/src/test/scala/cats/tests/ProdTests.scala b/tests/src/test/scala/cats/tests/ProdTests.scala
@@ -6,6 +6,7 @@ import cats.functor.Contravariant
 import cats.laws.discipline._
 import cats.laws.discipline.arbitrary._
 import cats.laws.discipline.eq._
+import cats.kernel.laws.OrderLaws
 
 class ProdTests extends CatsSuite {
   implicit val iso = CartesianTests.Isomorphisms.invariant[Prod[Option, List, ?]]
@@ -18,6 +19,8 @@ class ProdTests extends CatsSuite {
   checkAll("Prod[Show, Order, Int]", ContravariantTests[λ[α => Prod[Show, Order, α]]].contravariant[Int, Int, Int])
   checkAll("Contravariant[Prod[Show, Order, Int]]", SerializableTests.serializable(Contravariant[λ[α => Prod[Show, Order, α]]]))
 
+  checkAll("Show[Prod[Option, Option, Int]]", SerializableTests.serializable(Show[Prod[Option, Option, Int]]))
+
   {
     implicit val monoidK = ListWrapper.monoidK
     checkAll("Prod[ListWrapper, ListWrapper, ?]", MonoidKTests[Prod[ListWrapper, ListWrapper, ?]].monoidK[Int])
@@ -42,4 +45,49 @@ class ProdTests extends CatsSuite {
     checkAll("Prod[ListWrapper, ListWrapper, ?]", FunctorTests[Prod[ListWrapper, ListWrapper, ?]].functor[Int, Int, Int])
     checkAll("Functor[Prod[ListWrapper, ListWrapper, ?]]", SerializableTests.serializable(Functor[Prod[ListWrapper, ListWrapper, ?]]))
   }
+
+  {
+    implicit val monad = ListWrapper.monad
+    implicit val iso = CartesianTests.Isomorphisms.invariant[Prod[ListWrapper, ListWrapper, ?]]
+    checkAll("Prod[ListWrapper, ListWrapper, ?]", MonadTests[Prod[ListWrapper, ListWrapper, ?]].monad[Int, Int, Int])
+    checkAll("Monad[Prod[ListWrapper, ListWrapper, ?]]", SerializableTests.serializable(Monad[Prod[ListWrapper, ListWrapper, ?]]))
+  }
+
+  {
+    implicit val foldable = ListWrapper.foldable
+    checkAll("Prod[ListWrapper, ListWrapper, ?]", FoldableTests[Prod[ListWrapper, ListWrapper, ?]].foldable[Int, Int])
+    checkAll("Foldable[Prod[ListWrapper, ListWrapper, ?]]", SerializableTests.serializable(Foldable[Prod[ListWrapper, ListWrapper, ?]]))
+  }
+
+  {
+    implicit val traverse = ListWrapper.traverse
+    checkAll("Prod[ListWrapper, ListWrapper, ?]", TraverseTests[Prod[ListWrapper, ListWrapper, ?]].traverse[Int, Int, Int, Int, Option, Option])
+    checkAll("Traverse[Prod[ListWrapper, ListWrapper, ?]]", SerializableTests.serializable(Traverse[Prod[ListWrapper, ListWrapper, ?]]))
+  }
+
+  {
+    implicit val monadCombine = ListWrapper.monadCombine
+    implicit val iso = CartesianTests.Isomorphisms.invariant[Prod[ListWrapper, ListWrapper, ?]]
+    checkAll("Prod[ListWrapper, ListWrapper, ?]", MonadCombineTests[Prod[ListWrapper, ListWrapper, ?]].monadCombine[Int, Int, Int])
+    checkAll("MonadCombine[Prod[ListWrapper, ListWrapper, ?]]", SerializableTests.serializable(MonadCombine[Prod[ListWrapper, ListWrapper, ?]]))
+  }
+
+  {
+    implicit val E = ListWrapper.eqv[Int]
+    implicit val O = ListWrapper.order[Int]
+    implicit val P = ListWrapper.partialOrder[Int]
+
+    checkAll("Prod[ListWrapper, ListWrapper, Int]", OrderLaws[Prod[ListWrapper, ListWrapper, Int]].eqv)
+    checkAll("Prod[ListWrapper, ListWrapper, Int]", OrderLaws[Prod[ListWrapper, ListWrapper, Int]].order)
+    checkAll("Prod[ListWrapper, ListWrapper, Int]", OrderLaws[Prod[ListWrapper, ListWrapper, Int]].partialOrder)
+  }
+
+  test("show") {
+    forAll { (l1: Option[Int], l2: Option[Int]) =>
+      val prod = Prod(l1, l2)
+
+      Show[Prod[Option, Option, Int]].show(prod) should === (s"Prod(${Show[Option[Int]].show(l1)}, ${Show[Option[Int]].show(l2)})")
+    }
+  }
+
 }