相关疑难解决方法(0)

我有一个我输入的协议:

data ProtocolPacket
  = Packet1 Word8 Text Int8
  | Packet2 Text
  | Packet3 Int Text Text Text Text
  | Packet4 Int Double Double Double Int16 Int16 Int16
  ...
  deriving (Show,Eq)

另外,我已经为每个数据包实现了序列化/反序列化代码.当然,我想在Quickcheck中测试这个协议,并确保对任何输入组合的任何数据包进行序列化和反序列化都会让我准确地回复我所放入的内容.所以我继续为Arbitrary类型类实现这些数据包,如下所示:

instance Arbitrary ProtocolPacket where
  arbitrary = do
  packetID <- choose (0x00,...) :: Gen Word8
  case packetID of
    0x00 -> do
      a <- arbitrary
      b <- arbitrary
      c <- arbitrary
      return $ Packet1 a b c
    0x01 -> do
      a <- arbitrary
      return $ Packet2 a
    0x02 -> …