added hash conversion

typelevel · Dec 18, 2017 · 0f34e7c · 0f34e7c
1 parent b32a7c7
commit 0f34e7c
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Showing 4 changed files with 14 additions and 1 deletion.
diff --git a/core/src/main/scala/cats/instances/hash.scala b/core/src/main/scala/cats/instances/hash.scala
@@ -2,7 +2,7 @@ package cats
 package instances
 
 
-trait HashInstances {
+trait HashInstances extends kernel.instances.HashInstances {
 
   implicit val catsContravariantForHash: Contravariant[Hash] =
     new Contravariant[Hash] {

diff --git a/kernel/src/main/scala/cats/kernel/Hash.scala b/kernel/src/main/scala/cats/kernel/Hash.scala
@@ -54,3 +54,9 @@ object Hash extends HashFunctions[Hash] {
     }
 
 }
+
+trait HashToHashingConversion {
+  implicit def catsKernelHashToHashing[A](implicit ev: Hash[A]): Hashing[A] = new Hashing[A] {
+    override def hash(x: A): Int = ev.hash(x)
+  }
+}
diff --git a/kernel/src/main/scala/cats/kernel/instances/all.scala b/kernel/src/main/scala/cats/kernel/instances/all.scala
@@ -16,6 +16,7 @@ trait AllInstances
     with DurationInstances
     with FloatInstances
     with FunctionInstances
+    with HashInstances
     with IntInstances
     with ListInstances
     with LongInstances

diff --git a/kernel/src/main/scala/cats/kernel/instances/hash.scala b/kernel/src/main/scala/cats/kernel/instances/hash.scala
@@ -0,0 +1,6 @@
+package cats.kernel
+package instances
+
+trait HashInstances extends HashToHashingConversion
+
+object hash extends HashInstances