我是新的Haskell和我遇到了一些问题与我的递归解决方案。我将感谢任何和所有的帮助！
我的第一个目标是创建一个函数，检查字符串“A”，“B”和“C”的顺序，并输出一个整数数组，通过递归将每个字符串Map为一个数字。
我的第二个目标是创建一个函数，它可以使用两个整型数组（其中一个是从check_order创建的整数数组（由1、2和3组成），另一个是长度为3的随机整数数组），并返回一个字符串，使得1将被随机整数数组的第一个元素替换，2将被随机整数数组的第二个元素替换，等等。
下面是我的代码：

-- Takes any String consisting of namely A, B, and C and returns an Integer
-- with 1, 2, and 3 that corresponds to each particular character.
check_order :: String -> [Int]
check_order "" = []
check_order (x:xs)
    | x `elem` "A" = 1 : check_order xs
    | x `elem` "B" = 2 : check_order xs
    | otherwise    = 3 : check_order xs
    
-- Takes the integer array generated from check_order and an arbitrary
-- integer array of length 3 and returns a String correlating the check_order
-- array and the arbitrary integer array
number_correction :: Integral n => [n] -> [n] -> String
number_correction [] _ = ""
number_correction (x:xs) num_array
    | x == 1 = show (num_array !! 0) ++ " " ++ number_correction xs num_array
    | x == 2 = show (num_array !! 1) ++ " " ++ number_correction xs num_array
    | otherwise    = show (num_array !! 2) ++ " " ++ number_correction xs num_array
    
main = do
       let test = "ABCBABBAC";
       let num_array = [6, 1, 8];
       print(number_correction(check_order(test), num_array));
       
       --This print statement should print out "6 1 8 1 6 1 1 6 8"

以下是错误日志：

[1 of 1] Compiling Main             ( main.hs, main.o )
main.hs:12:16: error:• Could not deduce(Show n) arising from a use of ‘show’
      from the context: Integral n
        bound by the type signature for:number_correction :: Integral n => [n] -> [n] -> String
        at main.hs:9:1-55
      Possible fix:add (Show n) to the context of
          the type signature for:
            number_correction :: Integral n => [n] -> [n] -> String
    • In the firstargument of ‘(++)’, namely ‘show (num_array !! 0)’
      In the expression:
        show (num_array !! 0) ++ " " ++ number_correction xs num_array
      In anequation for ‘number_correction’:
          number_correction (x : xs) num_array
            | x == 1
            =show (num_array !! 0) ++ " " ++ number_correction xs num_array
            | x == 2
            = show (num_array !! 1) ++ " " ++ number_correction xs num_array
        | otherwise
            = show (num_array !! 2) ++ " " ++ number_correction xs num_array

main.hs:19:31: error:
    • Couldn't match expected type ‘[n0]’
        with actual type ‘([Int], [Integer])’
    • In the first argument of ‘number_correction’, namely
        ‘(check_order (test), num_array)’
      In the first argument of ‘print’, namely
        ‘(number_correction (check_order (test), num_array))’
      In a stmt of a'do' block:
        print (number_correction (check_order (test), num_array))