Rename prod coproduct (#1589)

* renamed Coproduct and Prod to EitherK and Tuple2K in code

* renamed files accordingly

core/src/main/scala/cats/Inject.scala

@@ -1,7 +1,7 @@
 package cats
 
 import cats.arrow.FunctionK
-import cats.data.Coproduct
+import cats.data.EitherK
 
 /**
  * Inject type class as described in "Data types a la carte" (Swierstra 2008).
@@ -26,18 +26,18 @@ private[cats] sealed abstract class InjectInstances {
       val prj = λ[FunctionK[F, λ[α => Option[F[α]]]]](Some(_))
     }
 
-  implicit def catsLeftInjectInstance[F[_], G[_]]: Inject[F, Coproduct[F, G, ?]] =
-    new Inject[F, Coproduct[F, G, ?]] {
-      val inj = λ[FunctionK[F, Coproduct[F, G, ?]]](Coproduct.leftc(_))
+  implicit def catsLeftInjectInstance[F[_], G[_]]: Inject[F, EitherK[F, G, ?]] =
+    new Inject[F, EitherK[F, G, ?]] {
+      val inj = λ[FunctionK[F, EitherK[F, G, ?]]](EitherK.leftc(_))
 
-      val prj = λ[FunctionK[Coproduct[F, G, ?], λ[α => Option[F[α]]]]](_.run.left.toOption)
+      val prj = λ[FunctionK[EitherK[F, G, ?], λ[α => Option[F[α]]]]](_.run.left.toOption)
     }
 
-  implicit def catsRightInjectInstance[F[_], G[_], H[_]](implicit I: Inject[F, G]): Inject[F, Coproduct[H, G, ?]] =
-    new Inject[F, Coproduct[H, G, ?]] {
-      val inj = λ[FunctionK[G, Coproduct[H, G, ?]]](Coproduct.rightc(_)) compose I.inj
+  implicit def catsRightInjectInstance[F[_], G[_], H[_]](implicit I: Inject[F, G]): Inject[F, EitherK[H, G, ?]] =
+    new Inject[F, EitherK[H, G, ?]] {
+      val inj = λ[FunctionK[G, EitherK[H, G, ?]]](EitherK.rightc(_)) compose I.inj
 
-      val prj = λ[FunctionK[Coproduct[H, G, ?], λ[α => Option[F[α]]]]](_.run.right.toOption.flatMap(I.prj(_)))
+      val prj = λ[FunctionK[EitherK[H, G, ?], λ[α => Option[F[α]]]]](_.run.right.toOption.flatMap(I.prj(_)))
     }
 }
 

core/src/main/scala/cats/arrow/FunctionK.scala

@@ -1,7 +1,7 @@
 package cats
 package arrow
 
-import cats.data.{Coproduct, Prod}
+import cats.data.{EitherK, Tuple2K}
 
 import cats.macros.MacroCompat
 
@@ -38,29 +38,29 @@ trait FunctionK[F[_], G[_]] extends Serializable { self =>
 
   /**
     * Composes two instances of FunctionK into a new FunctionK that transforms
-    * a [[cats.data.Coproduct]] to a single functor.
+    * a [[cats.data.EitherK]] to a single functor.
     *
     * This transformation will be used to transform left `F` values while
     * `h` will be used to transform right `H` values.
     */
-  def or[H[_]](h: FunctionK[H, G]): FunctionK[Coproduct[F, H, ?], G] =
-    λ[FunctionK[Coproduct[F, H, ?], G]](fa => fa.fold(self, h))
+  def or[H[_]](h: FunctionK[H, G]): FunctionK[EitherK[F, H, ?], G] =
+    λ[FunctionK[EitherK[F, H, ?], G]](fa => fa.fold(self, h))
 
   /**
    * Composes two instances of `FunctionK` into a new `FunctionK` that transforms
-   * one single functor to a [[cats.data.Prod]] of two functors.
+   * one single functor to a [[cats.data.Tuple2K]] of two functors.
    *
    * {{{
    * scala> import cats.arrow.FunctionK
    * scala> val list2option = λ[FunctionK[List, Option]](_.headOption)
    * scala> val list2vector = λ[FunctionK[List, Vector]](_.toVector)
    * scala> val optionAndVector = list2option and list2vector
    * scala> optionAndVector(List(1,2,3))
-   * res0: cats.data.Prod[Option,Vector,Int] = Prod(Some(1),Vector(1, 2, 3))
+   * res0: cats.data.Tuple2K[Option,Vector,Int] = Tuple2K(Some(1),Vector(1, 2, 3))
    * }}}
    */
-  def and[H[_]](h: FunctionK[F, H]): FunctionK[F, Prod[G, H, ?]] =
-    λ[FunctionK[F, Prod[G, H, ?]]](fa => Prod(self(fa), h(fa)))
+  def and[H[_]](h: FunctionK[F, H]): FunctionK[F, Tuple2K[G, H, ?]] =
+    λ[FunctionK[F, Tuple2K[G, H, ?]]](fa => Tuple2K(self(fa), h(fa)))
 }
 
 object FunctionK {