{-# LANGUAGE Trustworthy #-} {-# LANGUAGE CPP, NoImplicitPrelude, BangPatterns #-} ----------------------------------------------------------------------------- -- | -- 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. The Prelude is imported by default -- into all Haskell modules unless either there is an explicit import -- statement for it, or the NoImplicitPrelude extension is enabled. -- ----------------------------------------------------------------------------- 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, -- ** 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, ) where import Control.Monad import System.IO import System.IO.Error import Data.List import Data.Either import Data.Maybe import Data.Tuple import GHC.Base import Text.Read import GHC.Enum import GHC.Num import GHC.Real import GHC.Float import GHC.Show infixr 0 $! -- ----------------------------------------------------------------------------- -- Miscellaneous functions -- | Strict (call-by-value) application, defined in terms of 'seq'. ($!) :: (a -> b) -> a -> b f $! x = let !vx = x in f vx -- see #2273 #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