More examples

bijection-core/src/test/scala/com/twitter/bijection/TypeclassBijectionLaws.scala

@@ -8,12 +8,31 @@ class TypeclassBijectionLaws extends PropSpec with PropertyChecks with MustMatch
   import TypeclassBijection._
 
   case class A(x: Int, y: String)
-  implicit val bij: Bijection[A, (Int, String)] = Bijection.build[A, (Int, String)] { A.unapply(_).get } { x => A(x._1, x._2) }
+  implicit val abij: Bijection[A, (Int, String)] = Bijection.build[A, (Int, String)] { A.unapply(_).get } { x => A(x._1, x._2) }
 
   implicit val orderingTypeclassBijection: TypeclassBijection[Ordering] = new TypeclassBijection[Ordering] {
     def apply[A, B](tc: Ordering[A], bij: Bijection[A, B]) = tc.on { bij.invert(_) }
   }
 
+  implicit val numericTypeclassBijection: TypeclassBijection[Numeric] = new TypeclassBijection[Numeric] {
+    def apply[A, B](tc: Numeric[A], bij: Bijection[A, B]) =
+      new Numeric[B] {
+        def plus(x: B, y: B) = bij(tc.plus(bij.invert(x), bij.invert(y)))
+        def minus(x: B, y: B) = bij(tc.minus(bij.invert(x), bij.invert(y)))
+        def times(x: B, y: B) = bij(tc.times(bij.invert(x), bij.invert(y)))
+        def negate(x: B) = bij(tc.negate(bij.invert(x)))
+        def fromInt(x: Int) = bij(tc.fromInt(x))
+        def toInt(x: B) = tc.toInt(bij.invert(x))
+        def toLong(x: B) = tc.toLong(bij.invert(x))
+        def toFloat(x: B) = tc.toFloat(bij.invert(x))
+        def toDouble(x: B) = tc.toDouble(bij.invert(x))
+        def compare(x: B, y: B) = tc.compare(bij.invert(x), bij.invert(y))
+      }
+  }
+
+  case class Wrapper(get: Int)
+  implicit val wrapperbij: Bijection[Wrapper, Int] = Bijection.build[Wrapper, Int] { _.get } { Wrapper(_) }
+
   property("basic") {
     implicitly[Semigroup[Int]]
     implicitly[Semigroup[String]]
@@ -22,6 +41,8 @@ class TypeclassBijectionLaws extends PropSpec with PropertyChecks with MustMatch
     implicitly[Semigroup[(Int, String)]].bijectTo[A]
     deriveFor[Semigroup, A]
     deriveFor[Ordering, A]
+    deriveFor[Ordering, Wrapper]
+    deriveFor[Numeric, Wrapper]
   }
 }