124 lines
3.6 KiB
Haskell
124 lines
3.6 KiB
Haskell
{-# LANGUAGE CPP #-}
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{- |
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UTF-8 aware string IO functions that will work across multiple platforms
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and GHC versions. Includes code from Text.Pandoc.UTF8 ((C) 2010 John
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MacFarlane).
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Example usage:
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import Prelude hiding (readFile,writeFile,appendFile,getContents,putStr,putStrLn)
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import UTF8IOCompat (readFile,writeFile,appendFile,getContents,putStr,putStrLn)
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import UTF8IOCompat (SystemString,fromSystemString,toSystemString,error',userError')
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2013/4/10 update: we now trust that current GHC versions & platforms
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do the right thing, so this file is a no-op and on its way to being removed.
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Not carefully tested.
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-}
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-- TODO obsolete ?
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module Hledger.Utils.UTF8IOCompat (
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readFile,
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writeFile,
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appendFile,
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getContents,
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hGetContents,
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putStr,
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putStrLn,
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hPutStr,
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hPutStrLn,
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--
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SystemString,
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fromSystemString,
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toSystemString,
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error',
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userError',
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usageError,
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)
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where
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-- import Control.Monad (liftM)
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-- import qualified Data.ByteString.Lazy as B
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-- import qualified Data.ByteString.Lazy.Char8 as B8
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-- import qualified Data.ByteString.Lazy.UTF8 as U8 (toString, fromString)
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import Prelude hiding (readFile, writeFile, appendFile, getContents, putStr, putStrLn)
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import System.IO -- (Handle)
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-- bom :: B.ByteString
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-- bom = B.pack [0xEF, 0xBB, 0xBF]
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-- stripBOM :: B.ByteString -> B.ByteString
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-- stripBOM s | bom `B.isPrefixOf` s = B.drop 3 s
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-- stripBOM s = s
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-- readFile :: FilePath -> IO String
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-- readFile = liftM (U8.toString . stripBOM) . B.readFile
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-- writeFile :: FilePath -> String -> IO ()
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-- writeFile f = B.writeFile f . U8.fromString
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-- appendFile :: FilePath -> String -> IO ()
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-- appendFile f = B.appendFile f . U8.fromString
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-- getContents :: IO String
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-- getContents = liftM (U8.toString . stripBOM) B.getContents
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-- hGetContents :: Handle -> IO String
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-- hGetContents h = liftM (U8.toString . stripBOM) (B.hGetContents h)
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-- putStr :: String -> IO ()
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-- putStr = bs_putStr . U8.fromString
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-- putStrLn :: String -> IO ()
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-- putStrLn = bs_putStrLn . U8.fromString
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-- hPutStr :: Handle -> String -> IO ()
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-- hPutStr h = bs_hPutStr h . U8.fromString
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-- hPutStrLn :: Handle -> String -> IO ()
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-- hPutStrLn h = bs_hPutStrLn h . U8.fromString
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-- -- span GHC versions including 6.12.3 - 7.4.1:
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-- bs_putStr = B8.putStr
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-- bs_putStrLn = B8.putStrLn
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-- bs_hPutStr = B8.hPut
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-- bs_hPutStrLn h bs = B8.hPut h bs >> B8.hPut h (B.singleton 0x0a)
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-- | A string received from or being passed to the operating system, such
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-- as a file path, command-line argument, or environment variable name or
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-- value. With GHC versions before 7.2 on some platforms (posix) these are
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-- typically encoded. When converting, we assume the encoding is UTF-8 (cf
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-- <http://www.dwheeler.com/essays/fixing-unix-linux-filenames.html#UTF8>).
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type SystemString = String
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-- | Convert a system string to an ordinary string, decoding from UTF-8 if
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-- it appears to be UTF8-encoded and GHC version is less than 7.2.
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fromSystemString :: SystemString -> String
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fromSystemString = id
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-- | Convert a unicode string to a system string, encoding with UTF-8 if
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-- we are on a posix platform with GHC < 7.2.
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toSystemString :: String -> SystemString
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toSystemString = id
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-- | A SystemString-aware version of error.
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error' :: String -> a
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error' =
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#if __GLASGOW_HASKELL__ < 800
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-- (easier than if base < 4.9)
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error . toSystemString
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#else
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errorWithoutStackTrace . toSystemString
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#endif
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-- | A SystemString-aware version of userError.
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userError' :: String -> IOError
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userError' = userError . toSystemString
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-- | A SystemString-aware version of error that adds a usage hint.
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usageError :: String -> a
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usageError = error' . (++ " (use -h to see usage)")
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