anchor.diff:  /// for XML attribute properties
   type internal AttributeReaderInfo = {
       Info : System.Reflection.PropertyInfo
  -    Reader : string -> obj
  +    Reader : DeserializerFunc
       Setter : SetterFunc
       Ctor : EmptyConstructor }
   
  
positive.code: 
      let getValueParser t =
          match Type.GetTypeCode(t) with
          | TypeCode.Boolean -> Boolean.Parse >> box |> Some
          | TypeCode.Byte -> Byte.Parse >> box |> Some
          | TypeCode.Int16 -> Int16.Parse >> box |> Some
          | TypeCode.Int32 -> Int32.Parse >> box |> Some
          | TypeCode.Int64 -> Int64.Parse >> box |> Some
          | TypeCode.Char -> Char.Parse >> box |> Some
          | TypeCode.DateTime -> DateTime.Parse >> box |> Some
          | TypeCode.Decimal -> Decimal.Parse >> box |> Some
          | TypeCode.Double -> Double.Parse >> box |> Some
          | TypeCode.SByte -> SByte.Parse >> box |> Some
          | TypeCode.Single -> Single.Parse >> box |> Some
          | TypeCode.UInt16 -> UInt16.Parse >> box |> Some
          | TypeCode.UInt32 -> UInt32.Parse >> box |> Some
          | TypeCode.UInt64 -> UInt64.Parse >> box |> Some
          | TypeCode.String -> box |> Some
          | _ -> None
  
      let getValueReader (t : Type) = fun () ->
          match getValueParser t with
  
negative.code:     /// the specified PropertyInfo
      let getAttributeReaderInfo (p : PropertyInfo) : AttributeReaderInfo option =
          let t = p.PropertyType
          let reader =
              match XmlConfig.Instance.TryGetDeserializer t with
              | Some deserializer -> Some deserializer
              | None ->
                  match ValueTypeDeserializer.getValueParser t with
                  | Some parser -> Some <| DeserializerFunc(parser)
                  | None -> None
          match reader with
          | Some r ->
              { Info = p;
                Reader = r;
                Setter = ReflectionHelpers.getObjSetter p;
                Ctor = ReflectionHelpers.getConstructorMethod t } |> Some
          | None ->
  