在Haskell中创建没有参数的函数时出现分析错误

我试图创建一个没有参数的函数来创建一个列表。当我试图运行代码时，我得到一个解析错误，它无法编译，我不知道为什么

我一直试图在终端上运行它，但它不起作用

这是我的代码：

outfits = let pants = ["jeans", "khaki", "leggings"]
              shirts = ["white shirt", "grey turtleneck", "pink polo", "green hoodie"]
              shoes = ["brogues", "converse", "sandals", "adidas"]

outfits1 = [ (x, y, z) | z <- pants, y <- shirts, x <- shoes ]

oughts=let pants=[“牛仔裤”、“卡其色”、“紧身裤”]
衬衫=[“白色衬衫”、“灰色高领毛衣”、“粉色马球衫”、“绿色连帽衫”]
鞋=[“brogues”、“匡威”、“凉鞋”、“阿迪达斯”]
oughts1=[（x，y，z）| z如果没有
let
表达式，您只需编写

outfits = [ (x, y, z) | z <- ["jeans", "khaki", "leggings"], y <- ["white shirt", "grey turtleneck", "pink polo", "green hoodie"], x <- ["brogues", "converse", "sandals", "adidas"] ]

或者，您可以使用
where
子句编写此代码，该子句将“main”表达式放在第一位：

outfits = [ (x, y, z) | z <- pants, y <- shirts, x <- shoes ]
              where pants = ["jeans", "khaki", "leggings"]
                    shirts = ["white shirt", "grey turtleneck", "pink polo", "green hoodie"]
                    shoes = ["brogues", "converse", "sandals", "adidas"]

您仍然可以使用
let
表达式或
where
子句为装备的每个组件提供名称：

outfits = let pants = ["jeans", "khaki", "leggings"]
              shirts = ["white shirt", "grey turtleneck", "pink polo", "green hoodie"]
              shoes = ["brogues", "converse", "sandals", "adidas"]
          in (,,) <$> pants <*> shirts <*> shoes

oughts=let pants=[“牛仔裤”、“卡其色”、“紧身裤”]
衬衫=[“白色衬衫”、“灰色高领毛衣”、“粉色马球衫”、“绿色连帽衫”]
鞋=[“brogues”、“匡威”、“凉鞋”、“阿迪达斯”]
穿着（，）裤子衬衫鞋子

或

服装=（，）裤子衬衫鞋子
其中裤子=[“牛仔裤”、“卡其色”、“紧身裤”]
衬衫=[“白色衬衫”、“灰色高领毛衣”、“粉色马球衫”、“绿色连帽衫”]
鞋=[“brogues”、“匡威”、“凉鞋”、“阿迪达斯”]

---

如果

…..

看起来太深奥，您可以给模式一个更具描述性的名称：

outfits = mixAndMatch pants shirts shoes
           where pants = ["jeans", "khaki", "leggings"]
                 shirts = ["white shirt", "grey turtleneck", "pink polo", "green hoodie"]
                 shoes = ["brogues", "converse", "sandals", "adidas"]
                 mixAndMatch a b c = (,,) <$> a <*> b <*> c

oughts=mixAndMatch裤子衬衫鞋子
其中裤子=[“牛仔裤”、“卡其色”、“紧身裤”]
衬衫=[“白色衬衫”、“灰色高领毛衣”、“粉色马球衫”、“绿色连帽衫”]
鞋=[“brogues”、“匡威”、“凉鞋”、“阿迪达斯”]
mixAndMatch AB c=（，）AB c

let附带的

中的
在哪里？没有没有没有参数的函数。
oughts1
只是一个列表。
mixAndMatch=liftA3（，，）
，即使你不喜欢applicative样式，这可能更适合内联。或者，对于仍在学习语法的人来说，跳入applicative可能有点过分。@rampion
zip3
不会计算三个列表的叉积。
outfits = (,,) <$> ["jeans", "khaki", "leggings"]
               <*> ["white shirt", "grey turtleneck", "pink polo", "green hoodie"]
               <*> ["brogues", "converse", "sandals", "adidas"]

outfits = let pants = ["jeans", "khaki", "leggings"]
              shirts = ["white shirt", "grey turtleneck", "pink polo", "green hoodie"]
              shoes = ["brogues", "converse", "sandals", "adidas"]
          in (,,) <$> pants <*> shirts <*> shoes

outfits = (,,) <$> pants <*> shirts <*> shoes
              where pants = ["jeans", "khaki", "leggings"]
                    shirts = ["white shirt", "grey turtleneck", "pink polo", "green hoodie"]
                    shoes = ["brogues", "converse", "sandals", "adidas"]

outfits = mixAndMatch pants shirts shoes
           where pants = ["jeans", "khaki", "leggings"]
                 shirts = ["white shirt", "grey turtleneck", "pink polo", "green hoodie"]
                 shoes = ["brogues", "converse", "sandals", "adidas"]
                 mixAndMatch a b c = (,,) <$> a <*> b <*> c