Indirection via map traverse

broadinstitute · Sep 1, 2017 · b228d6b · b228d6b
1 parent 90e2d38
commit b228d6b
Showing 1 changed file with 7 additions and 2 deletions.
diff --git a/src/main/scala/lenthall/validation/ErrorOr.scala b/src/main/scala/lenthall/validation/ErrorOr.scala
@@ -23,8 +23,13 @@ object ErrorOr {
   }
 
   implicit class MapErrorOrRhs[A, B](val m: Map[A, ErrorOr[B]]) extends AnyVal {
-    private def elementToErrorOr(kvp: (A, ErrorOr[B])): ErrorOr[(A, B)] = kvp._2 map { v => (kvp._1, v) }
+    def sequence: ErrorOr[Map[A, B]] = m.traverseValues(identity)
+  }
+
+  implicit class MapTraversal[A, B](val m: Map[A, B]) extends AnyVal {
 
-    def sequence: ErrorOr[Map[A, B]] = m.toList.traverse[ErrorOr, (A, B)] { x => elementToErrorOr(x) } map { _.toMap }
+    def traverse[C,D](f: ((A,B)) => ErrorOr[(C,D)]): ErrorOr[Map[C,D]] = m.toList.traverse(f).map(_.toMap)
+    def traverseValues[C](f: B => ErrorOr[C]): ErrorOr[Map[A,C]] =
+      m.toList.traverse[ErrorOr, (A,C)] { case (a, b) => f(b).map(v => (a, v)) } map { _.toMap }
   }
 }