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We add the option -fno-implicit-prelude here to tell the reader that
special names such as () and -> shouldn't be resolved to Prelude.()
and Prelude.-> (as they are normally). -- SDM 8/10/97
\begin{code}
{-# OPTIONS -fno-implicit-prelude #-}
module Prelude (
-- Everything corresponding to the Report's PreludeList
module PrelList,
lines, words, unlines, unwords,
sum, product,
-- Everything corresponding to the Report's PreludeText
ReadS, ShowS,
Read(readsPrec, readList),
Show(showsPrec, showList, show),
reads, shows, read, lex,
showChar, showString, readParen, showParen,
-- Everything corresponding to the Report's PreludeIO
FilePath, IOError,
ioError, userError, catch,
putChar, putStr, putStrLn, print,
getChar, getLine, getContents, interact,
readFile, writeFile, appendFile, readIO, readLn,
Bool(..),
Maybe(..),
Either(..),
Ordering(..),
Char, String, Int, Integer, Float, Double, IO,
Rational,
[]((:), []),
module PrelTup,
-- Includes tuple types + fst, snd, curry, uncurry
()(..), -- The unit type
(->), -- functions
Eq(..),
Ord(..),
Enum(..),
Bounded(..),
Num((+), (-), (*), negate, abs, signum, fromInteger, fromInt{-glaExt-}),
Real(..),
Integral(quot, rem, div, mod, quotRem, divMod, toInteger, toInt{-partain-}),
Fractional(..),
Floating(..),
RealFrac(..),
RealFloat(..),
-- From Monad
Monad(..),
Functor(..),
mapM, mapM_, sequence, sequence_, (=<<),
maybe, either,
(&&), (||), not, otherwise,
subtract, even, odd, gcd, lcm, (^), (^^),
fromIntegral, realToFrac,
--exported by PrelTup: fst, snd, curry, uncurry,
id, const, (.), flip, ($), until,
asTypeOf, error, undefined,
seq, ($!)
) where
import PrelBase
import PrelList
#ifndef USE_REPORT_PRELUDE
hiding ( takeUInt_append )
#endif
import PrelRead
import PrelEnum
import PrelNum
import PrelNumExtra
import PrelTup
import PrelMaybe
import PrelShow
import PrelConc
import Monad
import Maybe
import PrelErr ( error )
import IO
infixr 0 $!
($!) :: (a -> b) -> a -> b
f $! x = x `seq` f x
-- It is expected that compilers will recognize this and insert error
-- messages which are more appropriate to the context in which undefined
-- appears.
undefined :: a
undefined = error "Prelude.undefined"
\end{code}
List sum and product are defined here because PrelList is too far
down the compilation chain to "see" the Num class.
\begin{code}
-- sum and product compute the sum or product of a finite list of numbers.
{-# SPECIALISE sum :: [Int] -> Int #-}
{-# SPECIALISE sum :: [Integer] -> Integer #-}
{-# SPECIALISE product :: [Int] -> Int #-}
{-# SPECIALISE product :: [Integer] -> Integer #-}
sum, product :: (Num a) => [a] -> a
#ifdef USE_REPORT_PRELUDE
sum = foldl (+) 0
product = foldl (*) 1
#else
sum l = sum' l 0
where
sum' [] a = a
sum' (x:xs) a = sum' xs (a+x)
product l = prod l 1
where
prod [] a = a
prod (x:xs) a = prod xs (a*x)
#endif
\end{code}
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