如何在kind的monads中重复一元指令？

import Control.Monad (guard)

-- 一元指令函数，判断一个数是否为偶数
isEven :: Int -> Maybe Bool
isEven n = do
  guard (n >= 0)  -- 添加守卫条件，确保输入为非负数
  return (even n)

-- 递归函数实现重复指令
repeatInstructionRecursive :: Int -> Maybe [Bool]
repeatInstructionRecursive n
  | n <= 0    = return []  -- 递归终止条件
  | otherwise = do
      result <- isEven n
      rest <- repeatInstructionRecursive (n - 1)
      return (result : rest)

-- 循环结构实现重复指令
repeatInstructionLoop :: Int -> Maybe [Bool]
repeatInstructionLoop n = do
  guard (n >= 0)  -- 添加守卫条件，确保输入为非负数
  sequence [isEven i | i <- [n, n-1 .. 1]]

-- 示例调用
main :: IO ()
main = do
  let n = 5
  putStrLn "Using recursive function:"
  print $ repeatInstructionRecursive n
  putStrLn "Using loop structure:"
  print $ repeatInstructionLoop n