[project @ 2000-05-10 15:16:11 by panne]

[ghc-hetmet.git] / ghc / lib / std / Prelude.lhs

diff --git a/ghc/lib/std/Prelude.lhs b/ghc/lib/std/Prelude.lhs
index 71a0378..237db71 100644 (file)
--- a/ghc/lib/std/Prelude.lhs
+++ b/ghc/lib/std/Prelude.lhs
@@ -43,15 +43,17 @@ module Prelude (
     Ord(..), 
     Enum(..),
     Bounded(..), 
-    Num((+), (-), (*), negate, abs, signum, fromInteger, fromInt{-glaExt-}),
+    Num((+), (-), (*), negate, abs, signum, fromInteger),
+       -- The fromInt method is exposed only by GlaExts
     Real(..),
-    Integral(quot, rem, div, mod, quotRem, divMod, toInteger, toInt{-partain-}),
+    Integral(quot, rem, div, mod, quotRem, divMod, toInteger),
+       -- The toInt method is exposed only by GlaExts
     Fractional(..),
     Floating(..),
     RealFrac(..),
     RealFloat(..),
 
-       -- From Monad
+       -- Monad stuff, from PrelBase, and defined here
     Monad(..),
     Functor(..), 
     mapM, mapM_, sequence, sequence_, (=<<),
@@ -68,22 +70,36 @@ module Prelude (
   ) where
 
 import PrelBase
-import PrelList hiding ( takeUInt_append )
+import PrelList
+#ifndef USE_REPORT_PRELUDE
+     hiding ( takeUInt_append )
+#endif
+import PrelIO
+import PrelIOBase
+import PrelException
 import PrelRead
 import PrelEnum
 import PrelNum
-import PrelNumExtra
+import PrelReal
+import PrelFloat
 import PrelTup
 import PrelMaybe
 import PrelShow
 import PrelConc
-import Monad
-import Maybe
 import PrelErr   ( error )
-import IO
 
+infixr 1 =<<
 infixr 0 $!
+\end{code}
+
+
+%*********************************************************
+%*                                                     *
+\subsection{Miscellaneous functions}
+%*                                                     *
+%*********************************************************
 
+\begin{code}
 ($!)    :: (a -> b) -> a -> b
 f $! x  = x `seq` f x
 
@@ -96,13 +112,21 @@ undefined               =  error "Prelude.undefined"
 \end{code}
 
 
+%*********************************************************
+%*                                                     *
+\subsection{List sum and product}
+%*                                                     *
+%*********************************************************
+
 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  
@@ -118,3 +142,87 @@ product    l       = prod l 1
     prod (x:xs) a = prod xs (a*x)
 #endif
 \end{code}
+
+
+%*********************************************************
+%*                                                     *
+\subsection{Prelude monad functions}
+%*                                                     *
+%*********************************************************
+
+\begin{code}
+{-# SPECIALISE (=<<) :: (a -> [b]) -> [a] -> [b] #-}
+(=<<)           :: Monad m => (a -> m b) -> m a -> m b
+f =<< x                = x >>= f
+
+sequence       :: Monad m => [m a] -> m [a] 
+{-# INLINE sequence #-}
+sequence ms = foldr k (return []) ms
+           where
+             k m m' = do { x <- m; xs <- m'; return (x:xs) }
+
+sequence_        :: Monad m => [m a] -> m () 
+{-# INLINE sequence_ #-}
+sequence_ ms     =  foldr (>>) (return ()) ms
+
+mapM            :: Monad m => (a -> m b) -> [a] -> m [b]
+{-# INLINE mapM #-}
+mapM f as       =  sequence (map f as)
+
+mapM_           :: Monad m => (a -> m b) -> [a] -> m ()
+{-# INLINE mapM_ #-}
+mapM_ f as      =  sequence_ (map f as)
+\end{code}
+
+
+%*********************************************************
+%*                                                     *
+\subsection{Coercions}
+%*                                                     *
+%*********************************************************
+
+\begin{code}
+{-# RULES
+"fromIntegral/Int->Int"                     fromIntegral   = id :: Int     -> Int
+"fromIntegral/Integer->Integer"             fromIntegral   = id :: Integer -> Integer
+"fromIntegral/Int->Integer"                 fromIntegral   = int2Integer
+"fromIntegral/Integer->Int"                 fromIntegral   = integer2Int
+"fromIntegral/Int->Rational"     forall n . fromIntegral n = int2Integer n :% 1
+"fromIntegral/Integer->Rational" forall n . fromIntegral n = n :% (1 :: Integer)
+"fromIntegral/Int->Float"                   fromIntegral   = int2Float
+"fromIntegral/Int->Double"                  fromIntegral   = int2Double
+"fromIntegral/Integer->Float"    forall n . fromIntegral n = encodeFloat n 0 :: Float
+"fromIntegral/Integer->Double"   forall n . fromIntegral n = encodeFloat n 0 :: Double
+ #-}
+fromIntegral   :: (Integral a, Num b) => a -> b
+fromIntegral   =  fromInteger . toInteger
+
+{-# RULES
+"realToFrac/Float->Double"      realToFrac = floatToDouble
+"realToFrac/Double->Float"      realToFrac = doubleToFloat
+"realToFrac/Float->Float"       realToFrac = id      :: Float    -> Float
+"realToFrac/Double->Double"     realToFrac = id      :: Double   -> Double
+"realToFrac/Rational->Rational" realToFrac = id      :: Rational -> Rational
+"realToFrac/Float->Rational"    realToFrac = rf2rat  :: Float    -> Rational
+"realToFrac/Double->Rational"   realToFrac = rf2rat  :: Double   -> Rational
+"realToFrac/Rational->Float"    realToFrac = fromRat :: Rational -> Float
+"realToFrac/Rational->Double"   realToFrac = fromRat :: Rational -> Double
+ #-}
+realToFrac     :: (Real a, Fractional b) => a -> b
+realToFrac     =  fromRational . toRational
+
+doubleToFloat :: Double -> Float
+doubleToFloat (D# d) = F# (double2Float# d)
+
+floatToDouble :: Float -> Double
+floatToDouble (F# f) = D# (float2Double# f)
+
+{-# SPECIALIZE rf2rat ::
+    Float  -> Rational,
+    Double -> Rational
+ #-}
+rf2rat :: RealFloat a => a -> Rational
+rf2rat x = if n >= 0 then (m * (b ^ n)) :% 1 else m :% (b ^ (-n))
+   where (m,n) = decodeFloat x
+         b     = floatRadix  x
+\end{code}