[project @ 2002-04-24 16:31:37 by simonmar]
[packages/base.git] / System / IO.hs
1 {-# OPTIONS -fno-implicit-prelude #-}
2 -----------------------------------------------------------------------------
3 -- |
4 -- Module : System.IO
5 -- Copyright : (c) The University of Glasgow 2001
6 -- License : BSD-style (see the file libraries/core/LICENSE)
7 --
8 -- Maintainer : libraries@haskell.org
9 -- Stability : provisional
10 -- Portability : portable
11 --
12 -- $Id: IO.hs,v 1.7 2002/04/24 16:31:45 simonmar Exp $
13 --
14 -- The standard IO library.
15 --
16 -----------------------------------------------------------------------------
17
18 module System.IO (
19 Handle, -- abstract, instance of: Eq, Show.
20 HandlePosn(..), -- abstract, instance of: Eq, Show.
21
22 IOMode(ReadMode,WriteMode,AppendMode,ReadWriteMode),
23 BufferMode(NoBuffering,LineBuffering,BlockBuffering),
24 SeekMode(AbsoluteSeek,RelativeSeek,SeekFromEnd),
25
26 stdin, stdout, stderr, -- :: Handle
27
28 openFile, -- :: FilePath -> IOMode -> IO Handle
29 hClose, -- :: Handle -> IO ()
30 hFileSize, -- :: Handle -> IO Integer
31 hIsEOF, -- :: Handle -> IO Bool
32 isEOF, -- :: IO Bool
33
34 hSetBuffering, -- :: Handle -> BufferMode -> IO ()
35 hGetBuffering, -- :: Handle -> IO BufferMode
36 hFlush, -- :: Handle -> IO ()
37 hGetPosn, -- :: Handle -> IO HandlePosn
38 hSetPosn, -- :: HandlePosn -> IO ()
39 hSeek, -- :: Handle -> SeekMode -> Integer -> IO ()
40 hTell, -- :: Handle -> IO Integer
41 hWaitForInput, -- :: Handle -> Int -> IO Bool
42 hReady, -- :: Handle -> IO Bool
43 hGetChar, -- :: Handle -> IO Char
44 hGetLine, -- :: Handle -> IO [Char]
45 hLookAhead, -- :: Handle -> IO Char
46 hGetContents, -- :: Handle -> IO [Char]
47 hPutChar, -- :: Handle -> Char -> IO ()
48 hPutStr, -- :: Handle -> [Char] -> IO ()
49 hPutStrLn, -- :: Handle -> [Char] -> IO ()
50 hPrint, -- :: Show a => Handle -> a -> IO ()
51 hIsOpen, hIsClosed, -- :: Handle -> IO Bool
52 hIsReadable, hIsWritable, -- :: Handle -> IO Bool
53 hIsSeekable, -- :: Handle -> IO Bool
54
55 isAlreadyExistsError, isDoesNotExistError, -- :: IOError -> Bool
56 isAlreadyInUseError, isFullError,
57 isEOFError, isIllegalOperation,
58 isPermissionError, isUserError,
59
60 ioeGetErrorString, -- :: IOError -> String
61 ioeGetHandle, -- :: IOError -> Maybe Handle
62 ioeGetFileName, -- :: IOError -> Maybe FilePath
63
64 try, -- :: IO a -> IO (Either IOError a)
65 bracket, -- :: IO a -> (a -> IO b) -> (a -> IO c) -> IO c
66 bracket_, -- :: IO a -> (a -> IO b) -> IO c -> IO c
67
68 -- Non-standard extension (but will hopefully become standard with 1.5) is
69 -- to export the Prelude io functions via IO (in addition to exporting them
70 -- from the prelude...for now.)
71 IO, -- instance MonadFix
72 FilePath, -- :: String
73 IOError,
74 ioError, -- :: IOError -> IO a
75 userError, -- :: String -> IOError
76 catch, -- :: IO a -> (IOError -> IO a) -> IO a
77 interact, -- :: (String -> String) -> IO ()
78
79 putChar, -- :: Char -> IO ()
80 putStr, -- :: String -> IO ()
81 putStrLn, -- :: String -> IO ()
82 print, -- :: Show a => a -> IO ()
83 getChar, -- :: IO Char
84 getLine, -- :: IO String
85 getContents, -- :: IO String
86 readFile, -- :: FilePath -> IO String
87 writeFile, -- :: FilePath -> String -> IO ()
88 appendFile, -- :: FilePath -> String -> IO ()
89 readIO, -- :: Read a => String -> IO a
90 readLn, -- :: Read a => IO a
91
92 hPutBuf, -- :: Handle -> Ptr a -> Int -> IO ()
93 hGetBuf, -- :: Handle -> Ptr a -> Int -> IO Int
94
95 fixIO, -- :: (a -> IO a) -> IO a
96
97 hSetEcho, -- :: Handle -> Bool -> IO ()
98 hGetEcho, -- :: Handle -> IO Bool
99
100 hIsTerminalDevice, -- :: Handle -> IO Bool
101 ) where
102
103 #ifdef __GLASGOW_HASKELL__
104 import GHC.Base
105 import GHC.IOBase -- Together these four Prelude modules define
106 import GHC.Handle -- all the stuff exported by IO for the GHC version
107 import GHC.IO
108 import GHC.ST ( fixST )
109 import GHC.Exception
110 import GHC.Num
111 import GHC.Read
112 import GHC.Show
113 #endif
114
115 import System.IO.Error
116
117 -- -----------------------------------------------------------------------------
118 -- Standard IO
119
120 putChar :: Char -> IO ()
121 putChar c = hPutChar stdout c
122
123 putStr :: String -> IO ()
124 putStr s = hPutStr stdout s
125
126 putStrLn :: String -> IO ()
127 putStrLn s = do putStr s
128 putChar '\n'
129
130 print :: Show a => a -> IO ()
131 print x = putStrLn (show x)
132
133 getChar :: IO Char
134 getChar = hGetChar stdin
135
136 getLine :: IO String
137 getLine = hGetLine stdin
138
139 getContents :: IO String
140 getContents = hGetContents stdin
141
142 interact :: (String -> String) -> IO ()
143 interact f = do s <- getContents
144 putStr (f s)
145
146 readFile :: FilePath -> IO String
147 readFile name = openFile name ReadMode >>= hGetContents
148
149 writeFile :: FilePath -> String -> IO ()
150 writeFile name str = do
151 hdl <- openFile name WriteMode
152 hPutStr hdl str
153 hClose hdl
154
155 appendFile :: FilePath -> String -> IO ()
156 appendFile name str = do
157 hdl <- openFile name AppendMode
158 hPutStr hdl str
159 hClose hdl
160
161 readLn :: Read a => IO a
162 readLn = do l <- getLine
163 r <- readIO l
164 return r
165
166 -- raises an exception instead of an error
167 readIO :: Read a => String -> IO a
168 readIO s = case (do { (x,t) <- reads s ;
169 ("","") <- lex t ;
170 return x }) of
171 [x] -> return x
172 [] -> ioError (userError "Prelude.readIO: no parse")
173 _ -> ioError (userError "Prelude.readIO: ambiguous parse")
174
175 hReady :: Handle -> IO Bool
176 hReady h = hWaitForInput h 0
177
178 hPutStrLn :: Handle -> String -> IO ()
179 hPutStrLn hndl str = do
180 hPutStr hndl str
181 hPutChar hndl '\n'
182
183 hPrint :: Show a => Handle -> a -> IO ()
184 hPrint hdl = hPutStrLn hdl . show
185
186 -- ---------------------------------------------------------------------------
187 -- fixIO
188
189 #ifdef __GLASGOW_HASKELL__
190 fixIO :: (a -> IO a) -> IO a
191 fixIO m = stToIO (fixST (ioToST . m))
192 #endif