shapeless_record.scala

case class JsonObject(fields: HList ) extends JsonValue

implicit def hlistObjectEncoder[K <: Symbol, H, T <: HList]( implicit
                                                             witness: Witness.Aux[K],
                                                             hEncoder: Lazy[JsonEncoder[H]],
                                                             tEncoder: JsonObjectEncoder[T]
                                                           ): JsonObjectEncoder[FieldType[K, H] :: T] = {
  val fieldName: String = witness.value.name
  createObjectEncoder { hlist =>
          val head = hEncoder.value.encode(hlist.head)
          val tail = tEncoder.encode(hlist.tail)
          JsonObject( (fieldName ->> head) :: tail.fields )
  }
}

////In the main method.

val iceCream = IceCream("Sundae", 1, 22.33, false)
val JsonObject(fields) = JsonEncoder[IceCream].encode(iceCream)
println ( fields )

println ( fields("numCherries") )