Merge pull request #705 from easel/xort-getorelsef

Add getOrElseF method to XorT
typelevel · Dec 1, 2015 · 0fcefbf · 0fcefbf
2 parents 399f645 + ec534f6
commit 0fcefbf
Show file tree

Hide file tree

Showing 2 changed files with 13 additions and 0 deletions.
diff --git a/core/src/main/scala/cats/data/XorT.scala b/core/src/main/scala/cats/data/XorT.scala
@@ -22,6 +22,13 @@ final case class XorT[F[_], A, B](value: F[A Xor B]) {
 
   def getOrElse[BB >: B](default: => BB)(implicit F: Functor[F]): F[BB] = F.map(value)(_.getOrElse(default))
 
+  def getOrElseF[BB >: B](default: => F[BB])(implicit F: Monad[F]): F[BB] = {
+    F.flatMap(value) {
+      case Xor.Left(_) => default
+      case Xor.Right(b) => F.pure(b)
+    }
+  }
+
   def recover(pf: PartialFunction[A, B])(implicit F: Functor[F]): XorT[F, A, B] =
     XorT(F.map(value)(_.recover(pf)))
 

diff --git a/tests/src/test/scala/cats/tests/XorTTests.scala b/tests/src/test/scala/cats/tests/XorTTests.scala
@@ -157,6 +157,12 @@ class XorTTests extends CatsSuite {
     }
   }
 
+  test("getOrElseF with Id consistent with Xor getOrElse") {
+    forAll { (xort: XorT[Id, String, Int], i: Int) =>
+      xort.getOrElseF(i) should === (xort.value.getOrElse(i))
+    }
+  }
+
   test("forall with Id consistent with Xor forall") {
     forAll { (xort: XorT[Id, String, Int], f: Int => Boolean) =>
       xort.forall(f) should === (xort.value.forall(f))