{-# OPTIONS_GHC -fno-implicit-prelude #-}
-----------------------------------------------------------------------------
-- |
-- Module : Prelude
-- Copyright : (c) The University of Glasgow 2001
-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : libraries@haskell.org
-- Stability : stable
-- Portability : portable
--
-- The Prelude: a standard module imported by default into all Haskell
-- modules. For more documentation, see the Haskell 98 Report
-- <http://www.haskell.org/onlinereport/>.
--
-----------------------------------------------------------------------------
module Prelude (
-- * Standard types, classes and related functions
-- ** Basic data types
Bool(False, True),
(&&), (||), not, otherwise,
Maybe(Nothing, Just),
maybe,
Either(Left, Right),
either,
Ordering(LT, EQ, GT),
Char, String,
-- *** 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
#endif
#ifdef __HUGS__
(:), -- Not legal Haskell 98
#endif
-- ** Basic type classes
Eq((==), (/=)),
Ord(compare, (<), (<=), (>=), (>), max, min),
Enum(succ, pred, toEnum, fromEnum, enumFrom, enumFromThen,
enumFromTo, enumFromThenTo),
Bounded(minBound, maxBound),
-- ** Numbers
-- *** Numeric types
Int, Integer, Float, Double,
Rational,
-- *** Numeric type classes
Num((+), (-), (*), negate, abs, signum, fromInteger),
Real(toRational),
Integral(quot, rem, div, mod, quotRem, divMod, toInteger),
Fractional((/), recip, fromRational),
Floating(pi, exp, log, sqrt, (**), logBase, sin, cos, tan,
asin, acos, atan, sinh, cosh, tanh, asinh, acosh, atanh),
RealFrac(properFraction, truncate, round, ceiling, floor),
RealFloat(floatRadix, floatDigits, floatRange, decodeFloat,
encodeFloat, exponent, significand, scaleFloat, isNaN,
isInfinite, isDenormalized, isIEEE, isNegativeZero, atan2),
-- *** Numeric functions
subtract, even, odd, gcd, lcm, (^), (^^),
fromIntegral, realToFrac,
-- ** Monads and functors
Monad((>>=), (>>), return, fail),
Functor(fmap),
mapM, mapM_, sequence, sequence_, (=<<),
-- ** Miscellaneous functions
id, const, (.), flip, ($), until,
asTypeOf, error, undefined,
seq, ($!),
-- * List operations
map, (++), filter,
head, last, tail, init, null, length, (!!),
reverse,
-- ** Reducing lists (folds)
foldl, foldl1, foldr, foldr1,
-- *** Special folds
and, or, any, all,
sum, product,
concat, concatMap,
maximum, minimum,
-- ** Building lists
-- *** Scans
scanl, scanl1, scanr, scanr1,
-- *** Infinite lists
iterate, repeat, replicate, cycle,
-- ** Sublists
take, drop, splitAt, takeWhile, dropWhile, span, break,
-- ** Searching lists
elem, notElem, lookup,
-- ** Zipping and unzipping lists
zip, zip3, zipWith, zipWith3, unzip, unzip3,
-- ** Functions on strings
lines, words, unlines, unwords,
-- * Converting to and from @String@
-- ** Converting to @String@
ShowS,
Show(showsPrec, showList, show),
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.
-- For example, two characters of input, return and linefeed, may
-- read as a single newline character. These functions cannot be
-- used portably for binary I/O.
-- *** Output functions
putChar,
putStr, putStrLn, print,
-- *** Input functions
getChar,
getLine, getContents, interact,
-- *** Files
FilePath,
readFile, writeFile, appendFile, readIO, readLn,
-- ** Exception handling in the I\/O monad
IOError, ioError, userError, catch
) where
#ifndef __HUGS__
import Control.Monad
import System.IO
import Text.Read
import Text.Show
import Data.List
import Data.Either
import Data.Maybe
import Data.Bool
import Data.Tuple
import Data.Eq
import Data.Ord
#endif
#ifdef __GLASGOW_HASKELL__
import GHC.Base
import GHC.IOBase
import GHC.Exception
import GHC.Read
import GHC.Enum
import GHC.Num
import GHC.Real
import GHC.Float
import GHC.Show
import GHC.Err ( error, undefined )
#endif
#ifdef __HUGS__
import Hugs.Prelude
#endif
#ifndef __HUGS__
infixr 0 $!
-- -----------------------------------------------------------------------------
-- Miscellaneous functions
-- | Strict (call-by-value) application, defined in terms of 'seq'.
($!) :: (a -> b) -> a -> b
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
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