Explore Derivation Of Functional Abstractions

core-tests/shared/src/test/scala-3/zio/prelude/DerivationSpec.scala

@@ -0,0 +1,31 @@
+package zio.prelude
+
+import zio._
+import zio.test._
+
+object DerivationSpec extends ZIOSpecDefault {
+
+  final case class Person(name: String, age: Int)
+
+  sealed trait Color
+
+  object Color {
+    case object Red   extends Color
+    case object Green extends Color
+    case object Blue  extends Color
+  }
+
+  def spec =
+    suite("DerivationSpec")(
+      suite("equal")(
+        test("case class") {
+          assertTrue(Person("Jane Doe", 42) === Person("Jane Doe", 42)) &&
+          assertTrue(Person("Jane Doe", 42) !== Person("John Doe", 42))
+        },
+        test("sealed trait") {
+          assertTrue(Color.Red === Color.Red) &&
+          assertTrue(Color.Red !== Color.Green)
+        }
+      )
+    )
+}

core/shared/src/main/scala-2/zio/prelude/EqualVersionSpecific.scala

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2023 John A. De Goes and the ZIO Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package zio.prelude
+
+trait EqualVersionSpecific

core/shared/src/main/scala-3/zio/prelude/EqualVersionSpecific.scala

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2023 John A. De Goes and the ZIO Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package zio.prelude
+
+import scala.deriving.*
+import scala.compiletime.{erasedValue, summonInline}
+
+trait EqualVersionSpecific {
+
+  inline given derived[A](using mirror: Mirror.Of[A]): Equal[A] =
+    val instances = summonAll[mirror.MirroredElemTypes]
+    inline mirror match
+      case sum: Mirror.SumOf[A] => equalSum(sum, instances)
+      case product: Mirror.ProductOf[A] => equalProduct(product, instances)
+
+  private inline def summonAll[A <: Tuple]: List[Equal[_]] =
+    inline erasedValue[A] match {
+      case _: EmptyTuple => Nil
+      case _: (t *: ts)  => summonInline[Equal[t]] :: summonAll[ts]
+    }
+
+  private def equalSum[A](sum: Mirror.SumOf[A], elems: List[Equal[_]]): Equal[A] =
+    Equal.make { (left, right) =>
+      val leftOrdinal = sum.ordinal(left)
+      val rightOrdinal = sum.ordinal(right)
+      (leftOrdinal == rightOrdinal) && check(elems(leftOrdinal))(left, right)
+    }
+
+  private def equalProduct[A](product: Mirror.ProductOf[A], elems: List[Equal[_]]): Equal[A] =
+    Equal.make { (left, right) =>
+      iterator(left).zip(iterator(right)).zip(elems.iterator).forall {
+        case ((l, r), elem) => check(elem)(l, r)
+      }
+    }
+
+  private def check(equal: Equal[_])(left: Any, right: Any): Boolean =
+    equal.asInstanceOf[Equal[Any]].equal(left, right)
+
+  private def iterator[A](a: A) =
+    a.asInstanceOf[Product].productIterator
+}

core/shared/src/main/scala/zio/prelude/Equal.scala

@@ -104,7 +104,7 @@ trait Equal[-A] { self =>
   def toScala[A1 <: A]: sm.Equiv[A1] = self.equal(_, _)
 }
 
-object Equal {
+object Equal extends EqualVersionSpecific {
 
   def fromScala[A](implicit equiv: sm.Equiv[A]): Equal[A] = equiv.equiv(_, _)
 

project/BuildHelper.scala

@@ -11,7 +11,7 @@ object BuildHelper {
   val Scala211: String = "2.11.12"
   val Scala212: String = "2.12.17"
   val Scala213: String = "2.13.10"
-  val Scala3: String   = "3.2.1"
+  val Scala3: String   = "3.2.2"
 
   val SilencerVersion = "1.7.12"