Add Text.IO.Utf8 module

src/Data/Text/IO/Utf8.hs

@@ -0,0 +1,44 @@
+-- |
+-- Module      : Data.Text.IO.Utf8
+-- Copyright   : (c) 2009, 2010 Bryan O'Sullivan,
+--               (c) 2009 Simon Marlow
+-- License     : BSD-style
+-- Maintainer  : [email protected]
+-- Portability : GHC
+--
+-- Efficient UTF-8 support for text I\/O.
+module Data.Text.IO.Utf8
+    (
+      readFile
+    , writeFile
+    , appendFile
+    ) where
+
+import Prelude hiding (readFile, writeFile, appendFile)
+import Control.Exception (evaluate)
+import Control.Monad ((<=<))
+import Data.ByteString (ByteString)
+import qualified Data.ByteString as B
+import Data.Text (Text)
+import Data.Text.Encoding (decodeUtf8, encodeUtf8)
+
+decodeUtf8IO :: ByteString -> IO Text
+decodeUtf8IO = evaluate . decodeUtf8
+
+encodeUtf8IO :: Text -> IO ByteString
+encodeUtf8IO = evaluate . encodeUtf8
+
+-- | The 'readFile' function reads a file and returns the contents of
+-- the file as a string.  The entire file is read strictly, as with
+-- 'getContents'.
+readFile :: FilePath -> IO Text
+readFile = decodeUtf8IO <=< B.readFile
+
+-- | Write a string to a file.  The file is truncated to zero length
+-- before writing begins.
+writeFile :: FilePath -> Text -> IO ()
+writeFile fp = B.writeFile fp <=< encodeUtf8IO
+
+-- | Write a string to the end of a file.
+appendFile :: FilePath -> Text -> IO ()
+appendFile fp = B.appendFile fp <=< encodeUtf8IO