% ------------------------------------------------------------------------------
-% $Id: PrelRead.lhs,v 1.17 2001/02/22 13:17:59 simonpj Exp $
+% $Id: PrelRead.lhs,v 1.20 2001/05/23 09:28:44 simonmar Exp $
%
% (c) The University of Glasgow, 1994-2000
%
module PrelRead where
-import PrelErr ( error )
+import {-# SOURCE #-} PrelErr ( error )
import PrelEnum ( Enum(..), maxBound )
import PrelNum
import PrelReal
import PrelMaybe
import PrelShow -- isAlpha etc
import PrelBase
-
--- needed for readIO and instance Read Buffermode
-import PrelIOBase ( IO, userError, BufferMode(..) )
-import PrelException ( ioError )
\end{code}
%*********************************************************
(x,str1) <- reads str
("","") <- lex str1
return x
-
- -- raises an exception instead of an error
-readIO :: Read a => String -> IO a
-readIO s = case (do { (x,t) <- reads s ; ("","") <- lex t ; return x }) of
-#ifndef NEW_READS_REP
- [x] -> return x
- [] -> ioError (userError "Prelude.readIO: no parse")
- _ -> ioError (userError "Prelude.readIO: ambiguous parse")
-#else
- Just x -> return x
- Nothing -> ioError (userError "Prelude.readIO: no parse")
-#endif
-
\end{code}
\begin{code}
ReadS Int,
ReadS Integer #-}
readDec :: (Integral a) => ReadS a
-readDec = readInt 10 isDigit (\d -> ord d - ord_0)
+readDec = readInt 10 isDigit (\d -> ord d - ord '0')
{-# SPECIALISE readOct ::
ReadS Int,
ReadS Integer #-}
readOct :: (Integral a) => ReadS a
-readOct = readInt 8 isOctDigit (\d -> ord d - ord_0)
+readOct = readInt 8 isOctDigit (\d -> ord d - ord '0')
{-# SPECIALISE readHex ::
ReadS Int,
ReadS Integer #-}
readHex :: (Integral a) => ReadS a
readHex = readInt 16 isHexDigit hex
- where hex d = ord d - (if isDigit d then ord_0
+ where hex d = ord d - (if isDigit d then ord '0'
else ord (if isUpper d then 'A' else 'a') - 10)
readInt :: (Integral a) => a -> (Char -> Bool) -> (Char -> Int) -> ReadS a
readInt radix isDig digToInt s = do
(ds,r) <- nonnull isDig s
- return (foldl1 (\n d -> n * radix + d) (map (fromInteger . int2Integer . digToInt) ds), r)
+ return (foldl1 (\n d -> n * radix + d)
+ (map (fromInteger . toInteger . digToInt) ds), r)
{-# SPECIALISE readSigned ::
ReadS Int -> ReadS Int,
#endif
\end{code}
-
-%*********************************************************
-%* *
-\subsection{Reading BufferMode}
-%* *
-%*********************************************************
-
-This instance decl is here rather than somewhere more appropriate in
-order that we can avoid both orphan-instance modules and recursive
-dependencies.
-
-\begin{code}
-instance Read BufferMode where
- readsPrec _ =
- readParen False
- (\r -> let lr = lex r
- in
- [(NoBuffering, rest) | ("NoBuffering", rest) <- lr] ++
- [(LineBuffering,rest) | ("LineBuffering",rest) <- lr] ++
- [(BlockBuffering mb,rest2) | ("BlockBuffering",rest1) <- lr,
- (mb, rest2) <- reads rest1])
-
-\end{code}