-%
-% (c) The AQUA Project, Glasgow University, 1994-1996
-%
-
-\section[PrelIO]{Module @PrelIO@}
-
-Input/output functions mandated by the standard Prelude.
-
-\begin{code}
-{-# OPTIONS -fno-implicit-prelude #-}
-
-module PrelIO (
- IO, FilePath, IOError,
- fail, userError, catch,
- putChar, putStr, putStrLn, print,
- getChar, getLine, getContents, interact,
- readFile, writeFile, appendFile, readIO, readLn
- ) where
-
-import IO
-import PrelHandle
-import PrelIOBase
-import PrelBase
-import PrelRead
-
-\end{code}
-
-\begin{code}
-putChar :: Char -> IO ()
-putChar c = hPutChar stdout c
-
-putStr :: String -> IO ()
-putStr s = hPutStr stdout s
-
-putStrLn :: String -> IO ()
-putStrLn s = do putStr s
- putChar '\n'
-
-print :: Show a => a -> IO ()
-print x = putStrLn (show x)
-
-getChar :: IO Char
-getChar = hGetChar stdin
-
-getLine :: IO String
-getLine = hGetLine stdin
-
-getContents :: IO String
-getContents = hGetContents stdin
-
-interact :: (String -> String) -> IO ()
-interact f = do s <- getContents
- putStr (f s)
-
-readFile :: FilePath -> IO String
-readFile name = openFile name ReadMode >>= hGetContents
-
-writeFile :: FilePath -> String -> IO ()
-writeFile name str
- = openFile name WriteMode >>= \hdl -> hPutStr hdl str >> hClose hdl
-
-appendFile :: FilePath -> String -> IO ()
-appendFile name str
- = openFile name AppendMode >>= \hdl -> hPutStr hdl str >> hClose hdl
-
-readIO :: Read a => String -> IO a
- -- raises an exception instead of an error
-readIO s = case [x | (x,t) <- reads s, ("","") <- lex t] of
- [x] -> return x
- [] -> fail (userError "PreludeIO.readIO: no parse")
- _ -> fail (userError
- "PreludeIO.readIO: ambiguous parse")
-
-readLn :: Read a => IO a
-readLn = do l <- getLine
- r <- readIO l
- return r
-\end{code}