-----------------------------------------------------------------------------
-- |
-- Module : GHC.Real
--- Copyright : (c) The FFI Task Force, 1994-2002
+-- Copyright : (c) The University of Glasgow, 1994-2002
-- License : see libraries/base/LICENSE
--
-- Maintainer : cvs-ghc@haskell.org
import GHC.List
import GHC.Enum
import GHC.Show
+import GHC.Err
infixr 8 ^, ^^
infixl 7 /, `quot`, `rem`, `div`, `mod`
-- | conversion to 'Integer'
toInteger :: a -> Integer
+ {-# INLINE quot #-}
+ {-# INLINE rem #-}
+ {-# INLINE div #-}
+ {-# INLINE mod #-}
n `quot` d = q where (q,_) = quotRem n d
n `rem` d = r where (_,r) = quotRem n d
n `div` d = q where (q,_) = divMod n d
n `mod` d = r where (_,r) = divMod n d
+
divMod n d = if signum r == negate (signum d) then (q-1, r+d) else qr
where qr@(q,r) = quotRem n d
-- @('Fractional' a) => a@.
fromRational :: Rational -> a
+ {-# INLINE recip #-}
+ {-# INLINE (/) #-}
recip x = 1 / x
x / y = x * recip y
properFraction :: (Integral b) => a -> (b,a)
-- | @'truncate' x@ returns the integer nearest @x@ between zero and @x@
truncate :: (Integral b) => a -> b
- -- | @'round' x@ returns the nearest integer to @x@
+ -- | @'round' x@ returns the nearest integer to @x@;
+ -- the even integer if @x@ is equidistant between two integers
round :: (Integral b) => a -> b
-- | @'ceiling' x@ returns the least integer not less than @x@
ceiling :: (Integral b) => a -> b
-- | @'floor' x@ returns the greatest integer not greater than @x@
floor :: (Integral b) => a -> b
+ {-# INLINE truncate #-}
truncate x = m where (m,_) = properFraction x
round x = let (n,r) = properFraction x
{-# SPECIALIZE instance Show Rational #-}
showsPrec p (x:%y) = showParen (p > ratioPrec) $
showsPrec ratioPrec1 x .
- showString "%" . -- H98 report has spaces round the %
- -- but we removed them [May 04]
+ showString " % " .
+ -- H98 report has spaces round the %
+ -- but we removed them [May 04]
+ -- and added them again for consistency with
+ -- Haskell 98 [Sep 08, #1920]
showsPrec ratioPrec1 y
instance (Integral a) => Enum (Ratio a) where
lcm 0 _ = 0
lcm x y = abs ((x `quot` (gcd x y)) * y)
+#ifdef OPTIMISE_INTEGER_GCD_LCM
{-# RULES
"gcd/Int->Int->Int" gcd = gcdInt
+"gcd/Integer->Integer->Integer" gcd = gcdInteger'
+"lcm/Integer->Integer->Integer" lcm = lcmInteger
#-}
--- XXX these optimisation rules are disabled for now to make it easier
--- to experiment with other Integer implementations
--- "gcd/Integer->Integer->Integer" gcd = gcdInteger'
--- "lcm/Integer->Integer->Integer" lcm = lcmInteger
---
--- gcdInteger' :: Integer -> Integer -> Integer
--- gcdInteger' 0 0 = error "GHC.Real.gcdInteger': gcd 0 0 is undefined"
--- gcdInteger' a b = gcdInteger a b
+gcdInteger' :: Integer -> Integer -> Integer
+gcdInteger' 0 0 = error "GHC.Real.gcdInteger': gcd 0 0 is undefined"
+gcdInteger' a b = gcdInteger a b
+
+gcdInt :: Int -> Int -> Int
+gcdInt 0 0 = error "GHC.Real.gcdInt: gcd 0 0 is undefined"
+gcdInt a b = fromIntegral (gcdInteger (fromIntegral a) (fromIntegral b))
+#endif
integralEnumFrom :: (Integral a, Bounded a) => a -> [a]
integralEnumFrom n = map fromInteger [toInteger n .. toInteger (maxBound `asTypeOf` n)]