Haskell中随机数生成的参数化界

我是Haskell的新手,我正在尝试创建一个函数,该函数生成一个有限数数组,并考虑一些起始和结束界限。如果我使用以下函数。。。

 finiteRandoms :: (Eq n, Num n, RandomGen g, Random a, Num a) => n -> g -> ([a], g)
 finiteRandoms 0 g = ([], g)
 finiteRandoms n g =
     let (value, newGen) = randomR (20,100) g
         (restOfList, finalGen) = finiteRandoms (n-1) newGen
     in  (value:restOfList, finalGen)

然后我运行以下命令。。。

finiteRandoms 3 (mkStdGen 3)

我用新的生成器获得了Int的数组

([61,33,82],StdGen {unStdGen = SMGen 9186733390819170434 2092789425003139053})

我要做的是向标记起点和终点的函数添加两个新参数。在我分享的函数中,它表示数字20和100。像这样的东西

finiteRandoms :: (Eq n, Num n, RandomGen g, Random a, Num a) => n -> n -> n-> g -> ([a], g)
   finiteRandoms 0 start end g = ([], g)
   finiteRandoms n start end g =
         let (value, newGen) = randomR (start,end) g
             (restOfList, finalGen) = finiteRandoms (n-1) newGen
         in  (value:restOfList, finalGen)

但是当我通过ghci加载它时,我会得到以下错误

randomSample.hs:19:10: error: [GHC-83865]
    • Couldn't match expected type: n -> g0 -> ([a0], g0)
                  with actual type: (a1, b)
    • In the pattern: (restOfList, finalGen)
      In a pattern binding:
        (restOfList, finalGen) = finiteRandoms (n - 1) newGen
      In the expression:
        let
          (value, newGen) = randomR (start, end) g
          (restOfList, finalGen) = finiteRandoms (n - 1) newGen
        in (value : restOfList, finalGen)
    • Relevant bindings include
        value :: n (bound at randomSample.hs:18:11)
        end :: n (bound at randomSample.hs:17:24)
        start :: n (bound at randomSample.hs:17:18)
        n :: n (bound at randomSample.hs:17:16)
        finiteRandoms :: n -> n -> n -> g -> ([a], g)
          (bound at randomSample.hs:16:2)
   |
19 |          (restOfList, finalGen) = finiteRandoms (n-1) newGen
   |          ^^^^^^^^^^^^^^^^^^^^^^

randomSample.hs:20:11: error: [GHC-25897]
    • Couldn't match expected type ‘a’ with actual type ‘n’
      ‘n’ is a rigid type variable bound by
        the type signature for:
          finiteRandoms :: forall n g a.
                           (Eq n, Num n, RandomGen g, Random a, Num a) =>
                           n -> n -> n -> g -> ([a], g)
        at randomSample.hs:15:2-92
      ‘a’ is a rigid type variable bound by
        the type signature for:
          finiteRandoms :: forall n g a.
                           (Eq n, Num n, RandomGen g, Random a, Num a) =>
                           n -> n -> n -> g -> ([a], g)
        at randomSample.hs:15:2-92
    • In the first argument of ‘(:)’, namely ‘value’
      In the expression: value : restOfList
      In the expression: (value : restOfList, finalGen)
    • Relevant bindings include
        value :: n (bound at randomSample.hs:18:11)
        end :: n (bound at randomSample.hs:17:24)
        start :: n (bound at randomSample.hs:17:18)
        n :: n (bound at randomSample.hs:17:16)
        finiteRandoms :: n -> n -> n -> g -> ([a], g)
          (bound at randomSample.hs:16:2)
   |
20 |      in  (value:restOfList, finalGen)
   |           ^^^^^
Failed, no modules loaded.

如何参数化这两个边界(开始/结束)?谢谢