CurryInfo: filepath-3.0.0 / System.FilePath.makeValid

makeValid :: FilePath -> FilePath
makeValid []                                     = "_"
makeValid path@(_:_)
  | isPosix                                      = path
  | length path >= 2 && all isPathSeparator path = take 2 path ++ "drive"
  | otherwise = joinDrive drv $ validElements $ validChars pth
 where
  (drv,pth) = splitDrive path
  validChars x = map f x
  f x | x `elem` badCharacters = '_'
      | otherwise = x
  validElements x = joinPath $ map g $ splitPath x
  g x = h (reverse b) ++ reverse a
      where (a,b) = span isPathSeparator $ reverse x
  h x = if map toUpper a `elem` badElements then a ++ "_" <.> b else x
      where (a,b) = splitExtensions x

argument 1

deterministic operation

-- | Take a FilePath and make it valid; does not change already valid FilePaths.
--
-- > isValid (makeValid x)
-- > isValid x ==> makeValid x == x
-- > makeValid "" == "_"
-- > Windows: makeValid "c:\\test:of_test" == "c:\\test_of_test"
-- > Windows: makeValid "test*" == "test_"
-- > Windows: makeValid "c:\\test\\nul" == "c:\\test\\nul_"
-- > Windows: makeValid "c:\\test\\prn.txt" == "c:\\test\\prn_.txt"
-- > Windows: makeValid "c:\\test/prn.txt" == "c:\\test/prn_.txt"
-- > Windows: makeValid "c:\\nul\\file" == "c:\\nul_\\file"

<FAILING>

referentially transparent operation

no fixity defined

{({[]}) |-> {:} || ({:}) |-> _}

makeValid

no precedence defined

_

String -> String

operation might suspend on free variables

possibly non-terminating

possibly non-reducible on same data term