在一个文件中，我试图定义一个这样的函数：
myReplicate ::（Int a）= > a - > b - > [b] myReplicate n x | n< = 0 = [] |否则= x：myReplicate（n-1）x当我尝试将文件加载到ghci时购买，我得到这个错误：
ghci>：l 1.hs [1 of 1] Compiling Main（1。 hs，解释） 1.hs：38：17：'Int'应用于太多类型参数在'myReplicate'的类型签名中： myReplicate :: Int a => a - > b - > [b] 失败，模块加载：无。ghci告诉我myReplicate的类型应该是：
ghci>：t myReplicate myReplicate ::（Num a，Ord a）=> a - > a1 - >如果我将类型声明更改为ghci推荐的内容：b
myReplicate ::（Num a，Ord a）=> a - > b - > [b]...然后函数编译和'工作'。然而，它是这样工作的：
ghci> myReplicate 3.2 1 [1,1,1,1 ]为什么我不能声明myReplicate只将Int作为第一个参数Int下降（？）来自Ord类的事实）？我想我可以把我的第一个后卫改成x< 1，这样myReplicate 3.2 1会生成[1,1,1，]，但为什么我必须打扰浮动？
解决方案Int是一个类型，而不是一个类型类型。你想要的是
myReplicate :: Int - > b - > [b]或者可能更精确的是
myReplicate :: Int - > Int - > [int]这是一个关于类型和类型类的好教程：learnyouahaskell/types-and-typeclasses
In a file, I'm trying to define a function like this:
myReplicate :: (Int a) => a -> b -> [b] myReplicate n x | n <= 0 = [] | otherwise = x : myReplicate (n-1) xBuy when I try loading the file into ghci, I get this error:
ghci>:l 1.hs [1 of 1] Compiling Main ( 1.hs, interpreted ) 1.hs:38:17: `Int' is applied to too many type arguments In the type signature for `myReplicate': myReplicate :: Int a => a -> b -> [b] Failed, modules loaded: none.ghci tells me that the type of myReplicate should be:
ghci>:t myReplicate myReplicate :: (Num a, Ord a) => a -> a1 -> [a1]If I change the type declaration to what ghci recommends:
myReplicate :: (Num a, Ord a) => a -> b -> [b]...then the function compiles and 'works'. However, it 'works' like this:
ghci>myReplicate 3.2 1 [1,1,1,1]Why can't I declare that myReplicate only takes an Int as the first argument (also in light of the fact that Int descends(?) from the Ord class)? I guess I could change my first guard to be x < 1, so that myReplicate 3.2 1 would produce [1, 1, 1,], but why do I have to bother with floats?
解决方案Int is a type, not a typeclass. What you want is
myReplicate :: Int -> b -> [b]or probably more precisely
myReplicate :: Int -> Int -> [Int]Here is a good tutorial on types and typeclasses: learnyouahaskell/types-and-typeclasses
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