Question

以下是我遇到问题的代码：

-----Function to test the postcondition----------------------------------
testPost :: Name -> Int -> [a] -> [b] -> IO ()
testPost _ _ [] [] = putStrLn "Test finished correctly"
testPost f_name n (t:ts) (o:os) = if (not aux_bool) then
                                         do putStr ("Failed on function " ++ (nameBase f_name) ++ " with inputs ")
                                            print ts
                                            putStr " and output "
                                            print os
                                            putStrLn ""
                                  else do
                                  do testPost f_name n ts os
                                      where aux_bool = post f_name n t o

编译器只是抱怨第一行：

C:\Users\pegartillo\Desktop\TFG\CaseGenerator\src\UUTReader.hs:205:1:
    parse error (possibly incorrect indentation or mismatched brackets)

我正在使用模板haskell库，这就是它出现Name数据类型的原因。

Answer 1

要让它编译，至少：

import Control.Monad (when)

newtype Name = Name { nameBase::String}

post _ _ _ _ = True

-----Function to test the postcondition----------------------------------
testPost :: (Show a,Show b) => Name -> Int -> [a] -> [b] -> IO ()
testPost _ _ [] [] = putStrLn "Test finished correctly"
testPost f_name n (t:ts) (o:os) = do
  when (not aux_bool) $ do
    putStr ("Failed on function " ++ (nameBase f_name) ++ " with inputs ")
    print ts
    putStr " and output "
    print os
    putStrLn ""
  testPost f_name n ts os
  where
    aux_bool = post f_name n t o

if-then-else和do的布局可能会变得棘手。就个人而言，如果可以的话，我尽量避免混合它们。可能有所帮助的是将每个块的主体拉出到自己的表达式中，以便在尝试调试时简化操作。

我得到Haskell“解析错误（可能是错误的缩进或不匹配的括号）”我看不出有什么问题

1 个答案: