Merge pull request #13 from drivergroup/symmetric-id-mapper

Make id type mappers bidirectional

2 files changed, 5 insertions, 3 deletions

diff --git a/src/main/scala/xyz/driver/core/core.scala b/src/main/scala/xyz/driver/core/core.scala
index 8c13aeb..1c92423 100644
--- a/src/main/scala/xyz/driver/core/core.scala
+++ b/src/main/scala/xyz/driver/core/core.scala
@@ -34,13 +34,17 @@ package core {
     override def toString: String = value
   }
 
+  @SuppressWarnings(Array("org.wartremover.warts.ImplicitConversion"))
   object Id {
     implicit def idEqual[T]: Equal[Id[T]]       = Equal.equal[Id[T]](_ == _)
     implicit def idOrdering[T]: Ordering[Id[T]] = Ordering.by[Id[T], String](_.value)
 
+    sealed trait Mapper[E, R]
     object Mapper {
-      def apply[A, B]: (Id[A] => Id[B]) = (id: Id[A]) => Id[B](id.value)
+      def apply[E, R] = new Mapper[E, R] {}
     }
+    implicit def convertRE[R, E](id: Id[R])(implicit ev: Mapper[E, R]): Id[E] = Id[E](id.value)
+    implicit def convertER[E, R](id: Id[E])(implicit ev: Mapper[E, R]): Id[R] = Id[R](id.value)
   }
 
   final case class Name[+Tag](value: String) extends AnyVal {
diff --git a/src/test/scala/xyz/driver/core/CoreTest.scala b/src/test/scala/xyz/driver/core/CoreTest.scala
index e210887..520fe8e 100644
--- a/src/test/scala/xyz/driver/core/CoreTest.scala
+++ b/src/test/scala/xyz/driver/core/CoreTest.scala
@@ -45,9 +45,7 @@ class CoreTest extends FlatSpec with Matchers with MockitoSugar {
     final case class Z(id: Id[Z])
 
     implicit val xy = Id.Mapper[X, Y]
-    implicit val yx = Id.Mapper[Y, X]
     implicit val yz = Id.Mapper[Y, Z]
-    implicit val zy = Id.Mapper[Z, Y]
 
     // The real test is that the following statements compile:
     val x  = X(Id("0"))