Added Bitraverse for Ior (#2144)

typelevel · Jan 23, 2018 · cc411db · cc411db
1 parent dbac00d
commit cc411db
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diff --git a/core/src/main/scala/cats/data/Ior.scala b/core/src/main/scala/cats/data/Ior.scala
@@ -145,6 +145,23 @@ object Ior extends IorInstances with IorFunctions {
 }
 
 private[data] sealed abstract class IorInstances extends IorInstances0 {
+
+  implicit val catsBitraverseForIor: Bitraverse[Ior] = new Bitraverse[Ior] {
+
+    def bitraverse[G[_], A, B, C, D](fab: Ior[A, B])(f: A => G[C], g: B => G[D])(implicit G: Applicative[G]): G[Ior[C, D]] =
+      fab.fold(
+        a => G.map(f(a))(Ior.Left(_)),
+        b => G.map(g(b))(Ior.Right(_)),
+        (a, b) => G.map2(f(a), g(b))(Ior.Both(_, _))
+      )
+
+    def bifoldLeft[A, B, C](fab: Ior[A, B], c: C)(f: (C, A) => C, g: (C, B) => C): C =
+      fab.fold(f(c, _), g(c, _), (a, b) => g(f(c, a), b))
+
+    def bifoldRight[A, B, C](fab: Ior[A, B], c: Eval[C])(f: (A, Eval[C]) => Eval[C], g: (B, Eval[C]) => Eval[C]): Eval[C] =
+      fab.fold(f(_, c), g(_, c), (a, b) => g(b, f(a, c)))
+  }
+
   implicit def catsDataEqForIor[A: Eq, B: Eq]: Eq[A Ior B] = new Eq[A Ior B] {
     def eqv(x: A Ior B, y: A Ior B): Boolean = x === y
   }

diff --git a/tests/src/test/scala/cats/tests/IorSuite.scala b/tests/src/test/scala/cats/tests/IorSuite.scala
@@ -23,6 +23,9 @@ class IorSuite extends CatsSuite {
   checkAll("Traverse[String Ior ?]", SerializableTests.serializable(Traverse[String Ior ?]))
   checkAll("? Ior ?", BifunctorTests[Ior].bifunctor[Int, Int, Int, String, String, String])
 
+  checkAll("Ior[?, ?]", BitraverseTests[Ior].bitraverse[Option, Int, Int, Int, String, String, String])
+  checkAll("Bitraverse[Ior]", SerializableTests.serializable(Bitraverse[Ior]))
+
   checkAll("Semigroup[Ior[A: Semigroup, B: Semigroup]]", SemigroupTests[Ior[List[Int], List[Int]]].semigroup)
   checkAll("SerializableTest Semigroup[Ior[A: Semigroup, B: Semigroup]]", SerializableTests.serializable(Semigroup[Ior[List[Int], List[Int]]]))