Adds Semigroup for Validated

Added a Semigroup for based on comment: https://github.com/non/cats/pull/715#issuecomment-162326224
mikejcurry · Dec 6, 2015 · ed3f768 · ed3f768
1 parent 48c38e5
commit ed3f768
Show file tree

Hide file tree

Showing 2 changed files with 8 additions and 0 deletions.
diff --git a/core/src/main/scala/cats/data/Validated.scala b/core/src/main/scala/cats/data/Validated.scala
@@ -236,6 +236,12 @@ private[data] sealed abstract class ValidatedInstances extends ValidatedInstance
 }
 
 private[data] sealed abstract class ValidatedInstances1 extends ValidatedInstances2 {
+
+  implicit def validatedSemigroup[A, B](implicit A: Semigroup[A], B: Semigroup[B]): Semigroup[Validated[A, B]] =
+    new Semigroup[Validated[A, B]] {
+      def combine(x: Validated[A, B], y: Validated[A, B]): Validated[A, B] = x combine y
+    }
+
   implicit def validatedPartialOrder[A: PartialOrder, B: PartialOrder]: PartialOrder[Validated[A,B]] =
     new PartialOrder[Validated[A,B]] {
       def partialCompare(x: Validated[A,B], y: Validated[A,B]): Double = x partialCompare y

diff --git a/tests/src/test/scala/cats/tests/ValidatedTests.scala b/tests/src/test/scala/cats/tests/ValidatedTests.scala
@@ -24,6 +24,8 @@ class ValidatedTests extends CatsSuite {
 
   checkAll("Monoid[Validated[String, Int]]", GroupLaws[Validated[String, Int]].monoid)
 
+  checkAll("Semigroup[Validated[String, NonEmptyList[Int]]]", GroupLaws[Validated[String, NonEmptyList[Int]]].semigroup)
+
   {
     implicit val S = ListWrapper.partialOrder[String]
     implicit val I = ListWrapper.partialOrder[Int]