Merge pull request #756 from nigredo-tori/589-cogen-domainof-redux

Add Cogen.domainOf (again)
typelevel · Feb 11, 2021 · 87c69f0 · 87c69f0
2 parents cade049 + 17d2e64
commit 87c69f0
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/src/main/scala/org/scalacheck/Cogen.scala b/src/main/scala/org/scalacheck/Cogen.scala
@@ -167,6 +167,8 @@ object Cogen extends CogenArities with CogenLowPriority with CogenVersionSpecifi
     while (i < as.length) { s = A.perturb(s, as(i)); i += 1 }
     s.next
   }
+
+  def domainOf[A, B](f: A => B)(implicit B: Cogen[B]): Cogen[A] = B.contramap(f)
 }
 
 trait CogenLowPriority {