remove trailing whitespace

[ghc-base.git] / GHC / Real.lhs

diff --git a/GHC/Real.lhs b/GHC/Real.lhs
index da6053e..bc63aeb 100644 (file)
--- a/GHC/Real.lhs
+++ b/GHC/Real.lhs
@@ -4,9 +4,9 @@
 -----------------------------------------------------------------------------
 -- |
 -- 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
 -- Stability   :  internal
 -- Portability :  non-portable (GHC Extensions)
@@ -24,12 +24,13 @@ import GHC.Num
 import GHC.List
 import GHC.Enum
 import GHC.Show
+import GHC.Err
 
 infixr 8  ^, ^^
 infixl 7  /, `quot`, `rem`, `div`, `mod`
 infixl 7  %
 
-default ()              -- Double isn't available yet, 
+default ()              -- Double isn't available yet,
                         -- and we shouldn't be using defaults anyway
 \end{code}
 
@@ -57,8 +58,8 @@ infinity, notANumber :: Rational
 infinity   = 1 :% 0
 notANumber = 0 :% 0
 
--- Use :%, not % for Inf/NaN; the latter would 
--- immediately lead to a runtime error, because it normalises. 
+-- Use :%, not % for Inf/NaN; the latter would
+-- immediately lead to a runtime error, because it normalises.
 \end{code}
 
 
@@ -132,10 +133,15 @@ class  (Real a, Enum a) => Integral a  where
     -- | 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
 
@@ -153,6 +159,8 @@ class  (Num a) => Fractional a  where
     -- @('Fractional' a) => a@.
     fromRational        :: Rational -> a
 
+    {-# INLINE recip #-}
+    {-# INLINE (/) #-}
     recip x             =  1 / x
     x / y               = x * recip y
 
@@ -173,15 +181,17 @@ class  (Real a, Fractional a) => RealFrac a  where
     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
                                m     = if r < 0 then n - 1 else n + 1
                            in case signum (abs r - 0.5) of
@@ -189,10 +199,10 @@ class  (Real a, Fractional a) => RealFrac a  where
                                 0  -> if even n then n else m
                                 1  -> m
                                 _  -> error "round default defn: Bad value"
-    
+
     ceiling x           =  if r > 0 then n + 1 else n
                            where (n,r) = properFraction x
-    
+
     floor x             =  if r < 0 then n - 1 else n
                            where (n,r) = properFraction x
 \end{code}
@@ -321,7 +331,10 @@ instance  (Integral a)  => Num (Ratio a)  where
 instance  (Integral a)  => Fractional (Ratio a)  where
     {-# SPECIALIZE instance Fractional Rational #-}
     (x:%y) / (x':%y')   =  (x*y') % (y*x')
-    recip (x:%y)        =  y % x
+    recip (0:%_)        = error "Ratio.%: zero denominator"
+    recip (x:%y)
+        | x < 0         = negate y :% negate x
+        | otherwise     = y :% x
     fromRational (x:%y) =  fromInteger x :% fromInteger y
 
 instance  (Integral a)  => Real (Ratio a)  where
@@ -336,7 +349,7 @@ instance  (Integral a)  => RealFrac (Ratio a)  where
 instance  (Integral a)  => Show (Ratio a)  where
     {-# SPECIALIZE instance Show Rational #-}
     showsPrec p (x:%y)  =  showParen (p > ratioPrec) $
-                           showsPrec ratioPrec1 x . 
+                           showsPrec ratioPrec1 x .
                            showString " % " .
                            -- H98 report has spaces round the %
                            -- but we removed them [May 04]
@@ -396,7 +409,7 @@ showSigned :: (Real a)
   -> Int                -- ^ the precedence of the enclosing context
   -> a                  -- ^ the value to show
   -> ShowS
-showSigned showPos p x 
+showSigned showPos p x
    | x < 0     = showParen (p > 6) (showChar '-' . showPos (-x))
    | otherwise = showPos x
 
@@ -447,19 +460,22 @@ lcm _ 0         =  0
 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 to use another Integer implementation, you might need to disable
--- the gcd/Integer and lcm/Integer RULES above
---
 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)]