[project @ 1998-08-27 13:07:56 by sof]

[ghc-hetmet.git] / ghc / lib / std / IO.lhs

diff --git a/ghc/lib/std/IO.lhs b/ghc/lib/std/IO.lhs
index 88051ee..0baa75a 100644 (file)
--- a/ghc/lib/std/IO.lhs
+++ b/ghc/lib/std/IO.lhs
@@ -59,6 +59,30 @@ module IO (
     bracket,                  -- :: IO a -> (a -> IO b) -> (a -> IO c) -> IO c
     bracket_,                 -- :: IO a -> (a -> IO b) -> IO c -> IO c
 
+    -- Non-standard extension (but will hopefully become standard with 1.5) is
+    -- to export the Prelude io functions via IO (in addition to exporting them
+    -- from the prelude...for now.) 
+    putChar,                  -- :: Char   -> IO ()
+    putStr,                   -- :: String -> IO () 
+    putStrLn,                 -- :: String -> IO ()
+    print,                    -- :: Show a => a -> IO ()
+    getChar,                  -- :: IO Char
+    getLine,                  -- :: IO String
+    getContents,              -- :: IO String
+    interact,                 -- :: (String -> String) -> IO ()
+    readFile,                 -- :: FilePath -> IO String
+    writeFile,                -- :: FilePath -> String -> IO ()
+    appendFile,                       -- :: FilePath -> String -> IO ()
+    readIO,                   -- :: Read a => String -> IO a
+    readLn,                   -- :: Read a => IO a
+    FilePath,                 -- :: String
+    fail,                     -- :: IOError -> IO a
+    catch,                    -- :: IO a    -> (IOError -> IO a) -> IO a
+    userError,                -- :: String  -> IOError
+
+    IO,                -- non-standard, amazingly enough.
+    IOError,    -- ditto
+
     -- extensions
     hPutBuf,
     hPutBufBA,
@@ -71,8 +95,10 @@ import PrelBase
 import PrelIOBase
 import PrelHandle              -- much of the real stuff is in here
 
-import PrelRead         ( readParen, Read(..), reads, lex )
-import PrelNum         ( toInteger )
+import PrelRead         ( readParen, Read(..), reads, lex,
+                         readIO 
+                       )
+--import PrelNum               ( toInteger )
 import PrelBounded      ()  -- Bounded Int instance.
 import PrelEither      ( Either(..) )
 import PrelAddr                ( Addr(..), nullAddr )
@@ -482,7 +508,7 @@ hPutStrLn hndl str = do
 %*                                                     *
 %*********************************************************
 
-The construct $try comp$ exposes errors which occur within a
+The construct @try comp@ exposes errors which occur within a
 computation, and which are not fully handled.  It always succeeds.
 
 \begin{code}
@@ -510,3 +536,61 @@ bracket_ before after m = do
             Right r -> return r
             Left  e -> fail e
 \end{code}
+
+%*********************************************************
+%*                                                      *
+\subsection{Standard IO}
+%*                                                      *
+%*********************************************************
+
+The Prelude has from Day 1 provided a collection of common
+IO functions. We define these here, but let the Prelude
+export them.
+
+\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 = do
+    hdl <- openFile name WriteMode
+    hPutStr hdl str
+    hClose hdl
+
+appendFile      :: FilePath -> String -> IO ()
+appendFile name str = do
+    hdl <- openFile name AppendMode
+    hPutStr hdl str
+    hClose hdl
+
+readLn          :: Read a => IO a
+readLn          =  do l <- getLine
+                      r <- readIO l
+                      return r
+\end{code}