私は自分の質問に答えて、考えられる答えの1つとして、現在実際に行っていることを次のように挙げようと思いました。もっとうまくやれる可能性は十分にあるので、私は質問をしています！しかし、私は以下を人々が利用できるようにすることは理にかなっていると思いました。これは基本的に、同じ問題に対するこのpython回避策のPythonからHaskellへの翻訳です。質問で言及されている「オプションB」を使用します。
基本的な考え方は、次のコンテンツを含むモジュールIOUtil.hsを作成importし、コードに組み込むことです。
{-# LANGUAGE ForeignFunctionInterface #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE NoImplicitPrelude #-}
module IOUtil (
IOUtil.interact,
IOUtil.putChar, IOUtil.putStr, IOUtil.putStrLn, IOUtil.print,
IOUtil.getChar, IOUtil.getLine, IOUtil.getContents, IOUtil.readIO,
IOUtil.readLn,
ePutChar, ePutStr, ePutStrLn, ePrint,
trace, traceIO
) where
#ifdef mingw32_HOST_OS
import System.Win32.Types (BOOL, HANDLE, DWORD, LPDWORD, LPWSTR, LPCWSTR, LPVOID)
import Foreign.C.Types (CWchar)
import Foreign
import Prelude hiding (getContents, putStr, putStrLn) --(IO, Read, Show, String)
--import qualified System.IO
import qualified System.IO (getContents)
import System.IO hiding (getContents, putStr, putStrLn)
import Data.Char (ord)
{- <http://msdn.microsoft.com/en-us/library/ms683231(VS.85).aspx>
HANDLE WINAPI GetStdHandle(DWORD nStdHandle);
returns INVALID_HANDLE_VALUE, NULL, or a valid handle -}
foreign import stdcall unsafe "GetStdHandle" win32GetStdHandle :: DWORD -> IO (HANDLE)
std_OUTPUT_HANDLE = -11 :: DWORD -- all DWORD arithmetic is performed modulo 2^n
std_ERROR_HANDLE = -12 :: DWORD
{- <http://msdn.microsoft.com/en-us/library/aa364960(VS.85).aspx>
DWORD WINAPI GetFileType(HANDLE hFile); -}
foreign import stdcall unsafe "GetFileType" win32GetFileType :: HANDLE -> IO (DWORD)
_FILE_TYPE_CHAR = 0x0002 :: DWORD
_FILE_TYPE_REMOTE = 0x8000 :: DWORD
{- <http://msdn.microsoft.com/en-us/library/ms683167(VS.85).aspx>
BOOL WINAPI GetConsoleMode(HANDLE hConsole, LPDWORD lpMode); -}
foreign import stdcall unsafe "GetConsoleMode" win32GetConsoleMode :: HANDLE -> LPDWORD -> IO (BOOL)
_INVALID_HANDLE_VALUE = (intPtrToPtr $ -1) :: HANDLE
is_a_console :: HANDLE -> IO (Bool)
is_a_console handle
= if (handle == _INVALID_HANDLE_VALUE) then return False
else do ft <- win32GetFileType handle
if ((ft .&. complement _FILE_TYPE_REMOTE) /= _FILE_TYPE_CHAR) then return False
else do ptr <- malloc
cm <- win32GetConsoleMode handle ptr
free ptr
return cm
real_stdout :: IO (Bool)
real_stdout = is_a_console =<< win32GetStdHandle std_OUTPUT_HANDLE
real_stderr :: IO (Bool)
real_stderr = is_a_console =<< win32GetStdHandle std_ERROR_HANDLE
{- BOOL WINAPI WriteConsoleW(HANDLE hOutput, LPWSTR lpBuffer, DWORD nChars,
LPDWORD lpCharsWritten, LPVOID lpReserved); -}
foreign import stdcall unsafe "WriteConsoleW" win32WriteConsoleW
:: HANDLE -> LPWSTR -> DWORD -> LPDWORD -> LPVOID -> IO (BOOL)
data ConsoleInfo = ConsoleInfo Int (Ptr CWchar) (Ptr DWORD) HANDLE
writeConsole :: ConsoleInfo -> [Char] -> IO ()
writeConsole (ConsoleInfo bufsize buf written handle) string
= let fillbuf :: Int -> [Char] -> IO ()
fillbuf i [] = emptybuf buf i []
fillbuf i remain@(first:rest)
| i + 1 < bufsize && ordf <= 0xffff = do pokeElemOff buf i asWord
fillbuf (i+1) rest
| i + 1 < bufsize && ordf > 0xffff = do pokeElemOff buf i word1
pokeElemOff buf (i+1) word2
fillbuf (i+2) rest
| otherwise = emptybuf buf i remain
where ordf = ord first
asWord = fromInteger (toInteger ordf) :: CWchar
sub = ordf - 0x10000
word1' = ((shiftR sub 10) .&. 0x3ff) + 0xD800
word2' = (sub .&. 0x3FF) + 0xDC00
word1 = fromInteger . toInteger $ word1'
word2 = fromInteger . toInteger $ word2'
emptybuf :: (Ptr CWchar) -> Int -> [Char] -> IO ()
emptybuf _ 0 [] = return ()
emptybuf _ 0 remain = fillbuf 0 remain
emptybuf ptr nLeft remain
= do let nLeft' = fromInteger . toInteger $ nLeft
ret <- win32WriteConsoleW handle ptr nLeft' written nullPtr
nWritten <- peek written
let nWritten' = fromInteger . toInteger $ nWritten
if ret && (nWritten > 0)
then emptybuf (ptr `plusPtr` (nWritten' * szWChar)) (nLeft - nWritten') remain
else fail "WriteConsoleW failed.\n"
in fillbuf 0 string
szWChar = sizeOf (0 :: CWchar)
makeConsoleInfo :: DWORD -> Handle -> IO (Either ConsoleInfo Handle)
makeConsoleInfo nStdHandle fallback
= do handle <- win32GetStdHandle nStdHandle
is_console <- is_a_console handle
let bufsize = 10000
if not is_console then return $ Right fallback
else do buf <- mallocBytes (szWChar * bufsize)
written <- malloc
return . Left $ ConsoleInfo bufsize buf written handle
{-# NOINLINE stdoutConsoleInfo #-}
stdoutConsoleInfo :: Either ConsoleInfo Handle
stdoutConsoleInfo = unsafePerformIO $ makeConsoleInfo std_OUTPUT_HANDLE stdout
{-# NOINLINE stderrConsoleInfo #-}
stderrConsoleInfo :: Either ConsoleInfo Handle
stderrConsoleInfo = unsafePerformIO $ makeConsoleInfo std_ERROR_HANDLE stderr
interact :: (String -> String) -> IO ()
interact f = do s <- getContents
putStr (f s)
conPutChar ci = writeConsole ci . replicate 1
conPutStr = writeConsole
conPutStrLn ci = writeConsole ci . ( ++ "\n")
putChar :: Char -> IO ()
putChar = (either conPutChar hPutChar ) stdoutConsoleInfo
putStr :: String -> IO ()
putStr = (either conPutStr hPutStr ) stdoutConsoleInfo
putStrLn :: String -> IO ()
putStrLn = (either conPutStrLn hPutStrLn) stdoutConsoleInfo
print :: Show a => a -> IO ()
print = putStrLn . show
getChar = System.IO.getChar
getLine = System.IO.getLine
getContents = System.IO.getContents
readIO :: Read a => String -> IO a
readIO = System.IO.readIO
readLn :: Read a => IO a
readLn = System.IO.readLn
ePutChar :: Char -> IO ()
ePutChar = (either conPutChar hPutChar ) stderrConsoleInfo
ePutStr :: String -> IO ()
ePutStr = (either conPutStr hPutStr ) stderrConsoleInfo
ePutStrLn :: String -> IO ()
ePutStrLn = (either conPutStrLn hPutStrLn) stderrConsoleInfo
ePrint :: Show a => a -> IO ()
ePrint = ePutStrLn . show
#else
import qualified System.IO
import Prelude (IO, Read, Show, String)
interact = System.IO.interact
putChar = System.IO.putChar
putStr = System.IO.putStr
putStrLn = System.IO.putStrLn
getChar = System.IO.getChar
getLine = System.IO.getLine
getContents = System.IO.getContents
ePutChar = System.IO.hPutChar System.IO.stderr
ePutStr = System.IO.hPutStr System.IO.stderr
ePutStrLn = System.IO.hPutStrLn System.IO.stderr
print :: Show a => a -> IO ()
print = System.IO.print
readIO :: Read a => String -> IO a
readIO = System.IO.readIO
readLn :: Read a => IO a
readLn = System.IO.readLn
ePrint :: Show a => a -> IO ()
ePrint = System.IO.hPrint System.IO.stderr
#endif
trace :: String -> a -> a
trace string expr = unsafePerformIO $ do
traceIO string
return expr
traceIO :: String -> IO ()
traceIO = ePutStrLn
次に、標準ライブラリの代わりに、そこに含まれているI/O関数を使用します。出力がリダイレクトされているかどうかを検出します。そうでない場合（つまり、「実際の」コンソールに書き込んでいる場合）、通常のHaskell I / O関数をバイパスしWriteConsoleW、Unicode対応のwin32コンソール関数を使用してwin32コンソールに直接書き込みます。Windows以外のプラットフォームでは、条件付きコンパイルとは、ここでの関数が標準ライブラリの関数を呼び出すことを意味します。
stderrに出力する必要がある場合は、;ePutStrLnではなく（eg）を使用する必要があります。hPutStrLn stderrを定義しませんhPutStrLn。（1つを定義することは読者のための練習です！）