build.sbt

scalaVersion := "2.11.6"

libraryDependencies ++= Seq(
  "com.chuusai" %% "shapeless" % "2.2.2"
)

eugene.scala

package net.tixxit.examples.eugene
import shapeless._
import shapeless.ops.hlist._

final case class LongType(x: Long)
final case class DoubleType(x: Double)
final case class StringType(x: String)

object convert extends Poly1 {
  implicit def convLong = at[LongType](_.x)
  implicit def convDouble = at[DoubleType](_.x)
  implicit def convString = at[StringType](_.x)
}

object Main extends App {
  val xs: LongType :: DoubleType :: StringType :: HNil =
    LongType(1) :: DoubleType(2D) :: StringType("3") :: HNil
  val ys: Long :: Double :: String :: HNil = xs.map(convert)

  println(xs)
  println(ys)
}