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|
{-# OPTIONS -fglasgow-exts -fno-implicit-prelude #-}
module PrelNum where
import {-# SOURCE #-} PrelErr
import PrelBase
import PrelList
import PrelEnum
import PrelShow
infixl 7 *
infixl 6 +, -
default () -- Double isn't available yet,
-- and we shouldn't be using defaults anyway
class (Eq a, Show a) => Num a where
(+), (-), (*) :: a -> a -> a
negate :: a -> a
abs, signum :: a -> a
fromInteger :: Integer -> a
fromInt :: Int -> a -- partain: Glasgow extension
x - y = x + negate y
negate x = 0 - x
fromInt (I# i#) = fromInteger (S# i#)
-- Go via the standard class-op if the
-- non-standard one ain't provided
subtract :: (Num a) => a -> a -> a
{-# INLINE subtract #-}
subtract x y = y - x
ord_0 :: Num a => a
ord_0 = fromInt (ord '0')
instance Num Int where
(+) x y = plusInt x y
(-) x y = minusInt x y
negate x = negateInt x
(*) x y = timesInt x y
abs n = if n `geInt` 0 then n else (negateInt n)
signum n | n `ltInt` 0 = negateInt 1
| n `eqInt` 0 = 0
| otherwise = 1
fromInt n = n
-- These can't go in PrelBase with the defn of Int, because
-- we don't have pairs defined at that time!
quotRemInt :: Int -> Int -> (Int, Int)
a@(I# _) `quotRemInt` b@(I# _) = (a `quotInt` b, a `remInt` b)
-- OK, so I made it a little stricter. Shoot me. (WDP 94/10)
divModInt :: Int -> Int -> (Int, Int)
divModInt x@(I# _) y@(I# _) = (x `divInt` y, x `modInt` y)
-- Stricter. Sorry if you don't like it. (WDP 94/10)
data Integer
= S# Int# -- small integers
| J# Int# ByteArray# -- large integers
zeroInteger :: Integer
zeroInteger = S# 0#
|
