DRYとか型安全を求めすぎて厨二病的なことになってる感じ

gistfile1.scala

sealed trait ReturnType{
  type A
  val func:(String => A)
}

object ReturnType{
  object IntType    extends ReturnType{ type A = Int    ; val func = (_:String).toInt }
  object LongType   extends ReturnType{ type A = Long   ; val func = (_:String).toLong }
  object StringType extends ReturnType{ type A = String ; val func = identity[String] _ }
}