[project @ 2002-07-16 16:08:58 by ross]
[packages/old-locale.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/base/LICENSE)
7 --
8 -- Maintainer : libraries@haskell.org
9 -- Stability : provisional
10 -- Portability : portable
11 --
12 -- The standard IO library.
13 --
14 -----------------------------------------------------------------------------
15
16 module System.IO (
17 Handle, -- abstract, instance of: Eq, Show.
18 HandlePosn(..), -- abstract, instance of: Eq, Show.
19
20 IOMode(ReadMode,WriteMode,AppendMode,ReadWriteMode),
21 BufferMode(NoBuffering,LineBuffering,BlockBuffering),
22 SeekMode(AbsoluteSeek,RelativeSeek,SeekFromEnd),
23
24 stdin, stdout, stderr, -- :: Handle
25
26 openFile, -- :: FilePath -> IOMode -> IO Handle
27 hClose, -- :: Handle -> IO ()
28 hFileSize, -- :: Handle -> IO Integer
29 hIsEOF, -- :: Handle -> IO Bool
30 isEOF, -- :: IO Bool
31
32 hSetBuffering, -- :: Handle -> BufferMode -> IO ()
33 hGetBuffering, -- :: Handle -> IO BufferMode
34 hFlush, -- :: Handle -> IO ()
35 hGetPosn, -- :: Handle -> IO HandlePosn
36 hSetPosn, -- :: HandlePosn -> IO ()
37 hSeek, -- :: Handle -> SeekMode -> Integer -> IO ()
38 #ifndef __HUGS__
39 hTell, -- :: Handle -> IO Integer
40 #endif
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 #ifndef __HUGS__
93 hPutBuf, -- :: Handle -> Ptr a -> Int -> IO ()
94 hGetBuf, -- :: Handle -> Ptr a -> Int -> IO Int
95 #endif
96
97 fixIO, -- :: (a -> IO a) -> IO a
98
99 #ifndef __HUGS__
100 hSetEcho, -- :: Handle -> Bool -> IO ()
101 hGetEcho, -- :: Handle -> IO Bool
102
103 hIsTerminalDevice, -- :: Handle -> IO Bool
104 #endif
105 ) where
106
107 #ifdef __GLASGOW_HASKELL__
108 import GHC.Base
109 import GHC.IOBase -- Together these four Prelude modules define
110 import GHC.Handle -- all the stuff exported by IO for the GHC version
111 import GHC.IO
112 import GHC.ST ( fixST )
113 import GHC.Exception
114 import GHC.Num
115 import GHC.Read
116 import GHC.Show
117 #endif
118
119 #ifdef __HUGS__
120 import Hugs.IO
121 import Hugs.IOExts
122 #endif
123
124 import System.IO.Error
125
126 -- -----------------------------------------------------------------------------
127 -- Standard IO
128
129 #ifndef __HUGS__
130 putChar :: Char -> IO ()
131 putChar c = hPutChar stdout c
132
133 putStr :: String -> IO ()
134 putStr s = hPutStr stdout s
135
136 putStrLn :: String -> IO ()
137 putStrLn s = do putStr s
138 putChar '\n'
139
140 print :: Show a => a -> IO ()
141 print x = putStrLn (show x)
142
143 getChar :: IO Char
144 getChar = hGetChar stdin
145
146 getLine :: IO String
147 getLine = hGetLine stdin
148
149 getContents :: IO String
150 getContents = hGetContents stdin
151
152 interact :: (String -> String) -> IO ()
153 interact f = do s <- getContents
154 putStr (f s)
155
156 readFile :: FilePath -> IO String
157 readFile name = openFile name ReadMode >>= hGetContents
158
159 writeFile :: FilePath -> String -> IO ()
160 writeFile name str = do
161 hdl <- openFile name WriteMode
162 hPutStr hdl str
163 hClose hdl
164
165 appendFile :: FilePath -> String -> IO ()
166 appendFile name str = do
167 hdl <- openFile name AppendMode
168 hPutStr hdl str
169 hClose hdl
170
171 readLn :: Read a => IO a
172 readLn = do l <- getLine
173 r <- readIO l
174 return r
175
176 -- raises an exception instead of an error
177 readIO :: Read a => String -> IO a
178 readIO s = case (do { (x,t) <- reads s ;
179 ("","") <- lex t ;
180 return x }) of
181 [x] -> return x
182 [] -> ioError (userError "Prelude.readIO: no parse")
183 _ -> ioError (userError "Prelude.readIO: ambiguous parse")
184 #endif /* __HUGS__ */
185
186 hReady :: Handle -> IO Bool
187 hReady h = hWaitForInput h 0
188
189 hPutStrLn :: Handle -> String -> IO ()
190 hPutStrLn hndl str = do
191 hPutStr hndl str
192 hPutChar hndl '\n'
193
194 hPrint :: Show a => Handle -> a -> IO ()
195 hPrint hdl = hPutStrLn hdl . show
196
197 -- ---------------------------------------------------------------------------
198 -- fixIO
199
200 #ifdef __GLASGOW_HASKELL__
201 fixIO :: (a -> IO a) -> IO a
202 fixIO m = stToIO (fixST (ioToST . m))
203 #endif