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我正在写一个猜牌游戏，这个游戏有3张目标牌，每次玩家选择3张牌作为他们的猜测。之后，玩家将收到一个 3 整数反馈，作为正确的牌、花色和等级的三倍，并返回一对下一次猜测和游戏状态。

到目前为止，我已经定义了自己的卡片类型。代码如下所示

data Suit = Club | Diamond | Heart | Spade
      deriving (Eq, Ord, Bounded, Enum, Show)


data Rank =
    R2 | R3 | R4 | R5 | R6 | R7 | R8 | R9 | R10 |
    Jack | Queen | King | Ace
        deriving (Eq, Ord, Bounded, Enum, Show)


data Card = Card {suit::Suit, rank::Rank}
          deriving (Eq, Bounded)

instance Ord Card where
    compare (Card s1 r1) (Card s2 r2) =
        let suitorder = compare s1 s2
        in  if suitorder == EQ then compare r1 r2 else suitorder

instance Enum Card where
    fromEnum (Card s r) = (fromEnum s)*13 + (fromEnum r)
    toEnum n = (Card s r)
      where s = toEnum (n `div` 13)
            r = toEnum (n `mod` 13)

instance Show Card where
    show (Card s r) = show r ++ show s


type GameState = [[Card]] -- store the remaining possible cards

现在我需要根据问题的要求编写2个函数

initialGuess :: ([String],GameState)

它不接受输入参数，并返回一对初始猜测和游戏状态

nextGuess :: ([String],GameState) -> (Int,Int,Int) -> ([String],GameState)

将一对先前的猜测和游戏状态、对这个猜测的反馈以及一对下一个猜测和游戏状态作为输入。

现在我必须将 [String] 转换为我定义的 [Card] 类型，但我坚持这种转换。

我目前的 initialGuess 如下所示

initialGuess::([String], GameState)
initialGuess = let guess = [(Card Club R2),(Card Club R3),(Card Club R4)]
                            gs = FilterGameState
                            in (guess, gs)
                            .....                 -not complete yet    

FilterGameState :: [[Card]]
FilterGameState = filter ([x,y,z]) decks
   where decks = [[x,y,z] | x <- [minBound..maxBound] :: [Card], 
                            y <- [minBound..maxBound] :: [Card],
                            z <- [minBound..maxBound] :: [Card]]

我仍然很难想出一种将 initialGuess 函数中的“猜测”转换为字符串的方法:(还有更多建议吗？？

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1 回答 1

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您可以将 Card 定义为 Read 的实例：

data Suit = Club | Diamond | Heart | Spade
      deriving (Eq, Ord, Bounded, Enum, Show, Read)


data Rank =
    R2 | R3 | R4 | R5 | R6 | R7 | R8 | R9 | R10 |
    Jack | Queen | King | Ace
        deriving (Eq, Ord, Bounded, Enum, Show, Read)


data Card = Card {suit::Suit, rank::Rank}
          deriving (Eq, Bounded)

instance Show Card where
  show (Card s1 r1) = show s1 ++ " " ++ show r1

instance Read Card where
  readsPrec i s = [(Card s1 r1, s'')
                  | (s1, s') <- readsPrec i s,
                    (r1, s'') <- readsPrec i s']

main = print $ (read "Club R3" :: Card)

（将卡片表示为字符串的方式略有变化）。

于 2013-09-17T16:56:33.950 回答