Rearranged and mapped some of the semi-autos from circe.derivation

build.sbt

@@ -2,9 +2,9 @@ import sbtcrossproject.{ CrossType, crossProject }
 
 val Scala212V = "2.12.17"
 val Scala213V = "2.13.7"
-val Scala3V = "3.2.0"
+val Scala3V = "3.2.2"
 
-val circeVersion = "0.14.3"
+val circeVersion = "0.14.5"
 val paradiseVersion = "2.1.1"
 
 val jawnVersion = "1.4.0"
@@ -100,9 +100,9 @@ lazy val benchmarks = project
   .settings(
     moduleName := "circe-generic-extras-benchmarks",
     libraryDependencies ++= List(
-      "io.circe" %%% "circe-parser" % circeVersion,
-      scalaOrganization.value % "scala-reflect" % scalaVersion.value
-    )
+      "io.circe" %%% "circe-parser" % circeVersion
+    ) ++ (if(scalaBinaryVersion.value.startsWith("2")) List(scalaOrganization.value % "scala-reflect" % scalaVersion.value)
+    else List.empty)
   )
   .dependsOn(genericExtras.jvm)
   .enablePlugins(JmhPlugin, NoPublishPlugin)

generic-extras/src/main/scala-2/io/circe/generic/extras/auto/package.scala

@@ -0,0 +1,9 @@
+package io.circe.generic.extras
+
+/**
+ * Fully automatic configurable codec derivation.
+ *
+ * Importing the contents of this package object provides [[io.circe.Decoder]] and [[io.circe.Encoder]] instances for
+ * case classes (if all members have instances), "incomplete" case classes, sealed trait hierarchies, etc.
+ */
+package object auto extends AutoDerivation

generic-extras/src/main/scala-2/io/circe/generic/extras/package.scala

@@ -1,9 +1,7 @@
-package io.circe.generic.extras
+package io.circe.generic
 
-/**
- * Fully automatic configurable codec derivation.
- *
- * Importing the contents of this package object provides [[io.circe.Decoder]] and [[io.circe.Encoder]] instances for
- * case classes (if all members have instances), "incomplete" case classes, sealed trait hierarchies, etc.
- */
-package object auto extends AutoDerivation
+import io.circe.Codec
+
+package object extras {
+  type ExtrasAsObjectCodec[A] = Codec.AsObject[A] with ExtrasDecoder[A]
+}

generic-extras/src/main/scala-3/io/circe/generic/extras/package.scala

@@ -0,0 +1,51 @@
+package io.circe.generic
+
+import io.circe.Codec
+import java.util.regex.Pattern
+
+package object extras {
+  type ExtrasAsObjectCodec[A] = Codec.AsObject[A] with ExtrasDecoder[A]
+  type Configuration = io.circe.derivation.Configuration
+
+  object Configuration {
+    def apply(
+      transformMemberNames: String => String = Predef.identity,
+      transformConstructorNames: String => String = Predef.identity,
+      useDefaults: Boolean = false,
+      discriminator: Option[String] = None,
+      strictDecoding: Boolean = false
+    ): Configuration = Configuration(
+      transformMemberNames = transformMemberNames,
+      transformConstructorNames = transformConstructorNames,
+      useDefaults = useDefaults,
+      discriminator = discriminator,
+      strictDecoding = strictDecoding
+    )
+
+    val default: Configuration = io.circe.derivation.Configuration.default
+    private val basePattern: Pattern = Pattern.compile("([A-Z]+)([A-Z][a-z])")
+    private val swapPattern: Pattern = Pattern.compile("([a-z\\d])([A-Z])")
+
+    val snakeCaseTransformation: String => String = s => {
+      val partial = basePattern.matcher(s).replaceAll("$1_$2")
+      swapPattern.matcher(partial).replaceAll("$1_$2").toLowerCase
+    }
+
+    val screamingSnakeCaseTransformation: String => String = s => {
+      val partial = basePattern.matcher(s).replaceAll("$1_$2")
+      swapPattern.matcher(partial).replaceAll("$1_$2").toUpperCase
+    }
+
+    val kebabCaseTransformation: String => String = s => {
+      val partial = basePattern.matcher(s).replaceAll("$1-$2")
+      swapPattern.matcher(partial).replaceAll("$1-$2").toLowerCase
+    }
+
+    val pascalCaseTransformation: String => String = s => {
+      s"${s.charAt(0).toUpper}${s.substring(1)}"
+    }
+  }
+  object defaults {
+    implicit val defaultGenericConfiguration: Configuration = Configuration.default
+  }
+}

generic-extras/src/main/scala-3/io/circe/generic/extras/semiauto.scala

@@ -23,15 +23,15 @@ import scala.deriving.Mirror
  * }}}
  */
 object semiauto {
-  inline final def deriveConfiguredDecoder[A](using inline A: Mirror.Of[A], configuration: Configuration): Decoder[A] = ???
-  inline final def deriveConfiguredEncoder[A](using inline A: Mirror.Of[A], configuration: Configuration): Encoder.AsObject[A] = ???
-  inline final def deriveConfiguredCodec[A](using inline A: Mirror.Of[A], configuration: Configuration): Codec.AsObject[A] = ???
+  inline final def deriveConfiguredDecoder[A](using inline A: Mirror.Of[A], configuration: Configuration): Decoder[A] = io.circe.derivation.ConfiguredDecoder.derived[A]
+  inline final def deriveConfiguredEncoder[A](using inline A: Mirror.Of[A], configuration: Configuration): Encoder.AsObject[A] = io.circe.derivation.ConfiguredEncoder.derived[A]
+  inline final def deriveConfiguredCodec[A](using inline A: Mirror.Of[A], configuration: Configuration): Codec.AsObject[A] = io.circe.derivation.ConfiguredCodec.derived[A]
 
   inline final def deriveExtrasDecoder[A](using inline A: Mirror.Of[A], configuration: Configuration): ExtrasDecoder[A] = ???
-  inline final def deriveExtrasEncoder[A](using inline A: Mirror.Of[A], configuration: Configuration): Encoder.AsObject[A] = ???
+  inline final def deriveExtrasEncoder[A](using inline A: Mirror.Of[A], configuration: Configuration): Encoder.AsObject[A] = deriveConfiguredEncoder[A]
   inline final def deriveExtrasCodec[A](using inline A: Mirror.Of[A], configuration: Configuration): ExtrasAsObjectCodec[A] = ???
 
-    /**
+  /**
    * Derive a decoder for a sealed trait hierarchy made up of case objects.
    *
    * Note that this differs from the usual derived decoder in that the leaves of the ADT are represented as JSON