Parsing Haskell:模式3中的分析错误_Parsing_Haskell_Design Patterns

Parsing Haskell:模式3中的分析错误

parsing haskell design-patterns

Parsing Haskell:模式3中的分析错误,parsing,haskell,design-patterns,Parsing,Haskell,Design Patterns,对Haskell来说比较新。想知道为什么我在尝试加载此文件后收到以下错误消息 data Peg = Red | Green | Blue | Yellow | Orange | Purple deriving (Show, Eq, Ord) type Code = [Peg] data Move = Move Code Int Int deriving (Show, Eq) isConsistent :: Move -> Code -> Bool isCon

对Haskell来说比较新。想知道为什么我在尝试加载此文件后收到以下错误消息

data Peg = Red | Green | Blue | Yellow | Orange | Purple
    deriving (Show, Eq, Ord)

type Code = [Peg]

data Move = Move Code Int Int
      deriving (Show, Eq)

isConsistent :: Move -> Code -> Bool
isConsistent (move1 code1 num1 num2) code2 = True --parse error here

move1

不是数据构造函数（这是允许模式匹配的），事实上也不是，因为它们必须以大写字母开头。将其替换为数据声明中的构造函数

Move

，错误就会消失

您可能仍然会收到一些警告，如“code1已定义但未使用”，如果您真的不关心内容，您可以通过将模式更改为

（Move\uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu@（移动代码int1 int2）

move1

现在指的是整个移动。

Parse error in pattern: move1