X-Git-Url: http://git.megacz.com/?p=ghc-base.git;a=blobdiff_plain;f=Prelude.hs;h=4c183ae38c9ad44a22a25c4bba5fa9149066cb62;hp=08fe811d76dc87d635531c613f1da6067ec6421e;hb=HEAD;hpb=69daab60bb6f89433a0394182481d721dc2f42fd

diff --git a/Prelude.hs b/Prelude.hs
index 08fe811..4c183ae 100644
--- a/Prelude.hs
+++ b/Prelude.hs
@@ -1,4 +1,5 @@
-{-# OPTIONS -fno-implicit-prelude #-}
+{-# LANGUAGE CPP, NoImplicitPrelude, BangPatterns #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Prelude
@@ -6,7 +7,7 @@
 -- License     :  BSD-style (see the file libraries/base/LICENSE)
 -- 
 -- Maintainer  :  libraries@haskell.org
--- Stability   :  provisional
+-- Stability   :  stable
 -- Portability :  portable
 --
 -- The Prelude: a standard module imported by default into all Haskell
@@ -31,22 +32,21 @@ module Prelude (
 
     Ordering(LT, EQ, GT),
     Char, String,
-    IO,
 
     -- *** Tuples
     fst, snd, curry, uncurry,
 
 #if defined(__NHC__)
-    []((:), []),	-- Not legal Haskell 98;
-			-- ... available through built-in syntax
-    module Data.Tuple,	-- Includes tuple types
-    ()(..),		-- Not legal Haskell 98
-    (->),		-- ... available through built-in syntax
+    []((:), []),        -- Not legal Haskell 98;
+                        -- ... available through built-in syntax
+    module Data.Tuple,  -- Includes tuple types
+    ()(..),             -- Not legal Haskell 98
+    (->),               -- ... available through built-in syntax
 #endif
 #ifdef __HUGS__
-    (:),		-- Not legal Haskell 98
+    (:),                -- Not legal Haskell 98
 #endif
-    
+
     -- ** Basic type classes
     Eq((==), (/=)),
     Ord(compare, (<), (<=), (>=), (>), max, min),
@@ -73,7 +73,7 @@ module Prelude (
               isInfinite, isDenormalized, isIEEE, isNegativeZero, atan2),
 
     -- *** Numeric functions
-    subtract, even, odd, gcd, lcm, (^), (^^), 
+    subtract, even, odd, gcd, lcm, (^), (^^),
     fromIntegral, realToFrac,
 
     -- ** Monads and functors
@@ -88,7 +88,7 @@ module Prelude (
 
     -- * List operations
     map, (++), filter,
-    head, last, tail, init, null, length, (!!), 
+    head, last, tail, init, null, length, (!!),
     reverse,
     -- ** Reducing lists (folds)
     foldl, foldl1, foldr, foldr1,
@@ -112,13 +112,18 @@ module Prelude (
     lines, words, unlines, unwords,
 
     -- * Converting to and from @String@
-    ReadS, ShowS,
-    Read(readsPrec, readList),
+    -- ** Converting to @String@
+    ShowS,
     Show(showsPrec, showList, show),
-    reads, shows, read, lex, 
-    showChar, showString, readParen, showParen,
-    
+    shows,
+    showChar, showString, showParen,
+    -- ** Converting from @String@
+    ReadS,
+    Read(readsPrec, readList),
+    reads, readParen, read, lex,
+
     -- * Basic Input and output
+    IO,
     -- ** Simple I\/O operations
     -- All I/O functions defined here are character oriented.  The
     -- treatment of the newline character will vary on different systems.
@@ -142,26 +147,24 @@ module Prelude (
 #ifndef __HUGS__
 import Control.Monad
 import System.IO
-import Text.Read
-import Text.Show
+import System.IO.Error
 import Data.List
 import Data.Either
 import Data.Maybe
-import Data.Bool
 import Data.Tuple
 #endif
 
 #ifdef __GLASGOW_HASKELL__
 import GHC.Base
-import GHC.IOBase
-import GHC.Exception
-import GHC.Read
+-- import GHC.IO
+-- import GHC.IO.Exception
+import Text.Read
 import GHC.Enum
 import GHC.Num
 import GHC.Real
 import GHC.Float
 import GHC.Show
-import GHC.Err   ( error, undefined )
+import GHC.Err   ( undefined )
 #endif
 
 #ifdef __HUGS__
@@ -170,12 +173,23 @@ import Hugs.Prelude
 
 #ifndef __HUGS__
 infixr 0 $!
-
+#endif
 
 -- -----------------------------------------------------------------------------
 -- Miscellaneous functions
 
+-- | Strict (call-by-value) application, defined in terms of 'seq'.
 ($!)    :: (a -> b) -> a -> b
+#ifdef __GLASGOW_HASKELL__
+f $! x  = let !vx = x in f vx  -- see #2273
+#elif !defined(__HUGS__)
 f $! x  = x `seq` f x
 #endif
 
+#ifdef __HADDOCK__
+-- | The value of @'seq' a b@ is bottom if @a@ is bottom, and otherwise
+-- equal to @b@.  'seq' is usually introduced to improve performance by
+-- avoiding unneeded laziness.
+seq :: a -> b -> b
+seq _ y = y
+#endif