+% -----------------------------------------------------------------------------
+% $Id: PrelBase.lhs,v 1.43 2001/03/01 09:23:40 qrczak Exp $
%
-% (c) The GRAP/AQUA Project, Glasgow University, 1992-1996
+% (c) The University of Glasgow, 1992-2000
%
\section[PrelBase]{Module @PrelBase@}
\begin{code}
{-# OPTIONS -fno-implicit-prelude #-}
+#include "MachDeps.h"
+
module PrelBase
(
module PrelBase,
- module PrelGHC -- Re-export PrelGHC, to avoid lots of people
- -- having to import it explicitly
+ module PrelGHC, -- Re-export PrelGHC and PrelErr, to avoid lots
+ module PrelErr -- of people having to import it explicitly
)
where
-import {-# SOURCE #-} PrelErr ( error )
import PrelGHC
+import {-# SOURCE #-} PrelErr
infixr 9 .
infixr 5 ++, :
%*********************************************************
%* *
+\subsection{DEBUGGING STUFF}
+%* (for use when compiling PrelBase itself doesn't work)
+%* *
+%*********************************************************
+
+\begin{code}
+{-
+data Bool = False | True
+data Ordering = LT | EQ | GT
+data Char = C# Char#
+type String = [Char]
+data Int = I# Int#
+data () = ()
+data [] a = MkNil
+
+not True = False
+(&&) True True = True
+otherwise = True
+
+build = error "urk"
+foldr = error "urk"
+
+unpackCString# :: Addr# -> [Char]
+unpackFoldrCString# :: Addr# -> (Char -> a -> a) -> a -> a
+unpackAppendCString# :: Addr# -> [Char] -> [Char]
+unpackCStringUtf8# :: Addr# -> [Char]
+unpackCString# a = error "urk"
+unpackFoldrCString# a = error "urk"
+unpackAppendCString# a = error "urk"
+unpackCStringUtf8# a = error "urk"
+-}
+\end{code}
+
+
+%*********************************************************
+%* *
\subsection{Standard classes @Eq@, @Ord@}
%* *
%*********************************************************
\begin{code}
class Eq a where
- (==), (/=) :: a -> a -> Bool
+ (==), (/=) :: a -> a -> Bool
- x /= y = not (x == y)
- x == y = not (x /= y)
+ x /= y = not (x == y)
+ x == y = not (x /= y)
class (Eq a) => Ord a where
- compare :: a -> a -> Ordering
- (<), (<=), (>=), (>):: a -> a -> Bool
- max, min :: a -> a -> a
+ compare :: a -> a -> Ordering
+ (<), (<=), (>), (>=) :: a -> a -> Bool
+ max, min :: a -> a -> a
+
+ -- An instance of Ord should define either 'compare' or '<='.
+ -- Using 'compare' can be more efficient for complex types.
--- An instance of Ord should define either compare or <=
--- Using compare can be more efficient for complex types.
compare x y
- | x == y = EQ
- | x <= y = LT -- NB: must be '<=' not '<' to validate the
- -- above claim about the minimal things that can
- -- be defined for an instance of Ord
- | otherwise = GT
-
- x <= y = case compare x y of { GT -> False; _other -> True }
- x < y = case compare x y of { LT -> True; _other -> False }
- x >= y = case compare x y of { LT -> False; _other -> True }
- x > y = case compare x y of { GT -> True; _other -> False }
-
- -- These two default methods use '>' rather than compare
+ | x == y = EQ
+ | x <= y = LT -- NB: must be '<=' not '<' to validate the
+ -- above claim about the minimal things that
+ -- can be defined for an instance of Ord
+ | otherwise = GT
+
+ x < y = case compare x y of { LT -> True; _other -> False }
+ x <= y = case compare x y of { GT -> False; _other -> True }
+ x > y = case compare x y of { GT -> True; _other -> False }
+ x >= y = case compare x y of { LT -> False; _other -> True }
+
+ -- These two default methods use '<=' rather than 'compare'
-- because the latter is often more expensive
- max x y = if x > y then x else y
- min x y = if x > y then y else x
+ max x y = if x <= y then y else x
+ min x y = if x <= y then x else y
\end{code}
%*********************************************************
\begin{code}
class Functor f where
- fmap :: (a -> b) -> f a -> f b
+ fmap :: (a -> b) -> f a -> f b
class Monad m where
(>>=) :: m a -> (a -> m b) -> m b
m >> k = m >>= \_ -> k
fail s = error s
-
\end{code}
data [] a = [] | a : [a] -- do explicitly: deriving (Eq, Ord)
-- to avoid weird names like con2tag_[]#
+
instance (Eq a) => Eq [a] where
{-# SPECIALISE instance Eq [Char] #-}
- [] == [] = True
+ [] == [] = True
(x:xs) == (y:ys) = x == y && xs == ys
- _xs == _ys = False
-
- xs /= ys = if (xs == ys) then False else True
+ _xs == _ys = False
instance (Ord a) => Ord [a] where
{-# SPECIALISE instance Ord [Char] #-}
- a < b = case compare a b of { LT -> True; EQ -> False; GT -> False }
- a <= b = case compare a b of { LT -> True; EQ -> True; GT -> False }
- a >= b = case compare a b of { LT -> False; EQ -> True; GT -> True }
- a > b = case compare a b of { LT -> False; EQ -> False; GT -> True }
compare [] [] = EQ
- compare (_:_) [] = GT
compare [] (_:_) = LT
+ compare (_:_) [] = GT
compare (x:xs) (y:ys) = case compare x y of
- LT -> LT
- GT -> GT
- EQ -> compare xs ys
+ EQ -> compare xs ys
+ other -> other
instance Functor [] where
fmap = map
foldr k z xs = go xs
where
go [] = z
- go (x:xs) = x `k` go xs
+ go (y:ys) = y `k` go ys
build :: forall a. (forall b. (a -> b -> b) -> b -> b) -> [a]
{-# INLINE 2 build #-}
"foldr/cons" forall k z x xs. foldr k z (x:xs) = k x (foldr k z xs)
"foldr/nil" forall k z. foldr k z [] = z
+
+"augment/build" forall (g::forall b. (a->b->b) -> b -> b)
+ (h::forall b. (a->b->b) -> b -> b) .
+ augment g (build h) = build (\c n -> g c (h c n))
+"augment/nil" forall (g::forall b. (a->b->b) -> b -> b) .
+ augment g [] = build g
#-}
+
+-- This rule is true, but not (I think) useful:
+-- augment g (augment h t) = augment (\cn -> g c (h c n)) t
\end{code}
\begin{code}
map :: (a -> b) -> [a] -> [b]
-{-# INLINE map #-}
-map f xs = build (\c n -> foldr (mapFB c f) n xs)
+map = mapList
-- Note eta expanded
+mapFB :: (elt -> lst -> lst) -> (a -> elt) -> a -> lst -> lst
mapFB c f x ys = c (f x) ys
mapList :: (a -> b) -> [a] -> [b]
mapList f (x:xs) = f x : mapList f xs
{-# RULES
+"map" forall f xs. map f xs = build (\c n -> foldr (mapFB c f) n xs)
"mapFB" forall c f g. mapFB (mapFB c f) g = mapFB c (f.g)
"mapList" forall f. foldr (mapFB (:) f) [] = mapList f
#-}
----------------------------------------------
\begin{code}
(++) :: [a] -> [a] -> [a]
-{-# INLINE (++) #-}
-xs ++ ys = augment (\c n -> foldr c n xs) ys
+(++) = append
+
+{-# RULES
+ "++" forall xs ys. (++) xs ys = augment (\c n -> foldr c n xs) ys
+ #-}
append :: [a] -> [a] -> [a]
append [] ys = ys
%*********************************************************
\begin{code}
-type String = [Char]
+type String = [Char]
data Char = C# Char#
(C# c1) < (C# c2) = c1 `ltChar#` c2
chr :: Int -> Char
-chr (I# i) | i >=# 0# && i <=# 255# = C# (chr# i)
- | otherwise = error ("Prelude.chr: bad argument")
+chr (I# i) | i >=# 0# && i <=# 0x10FFFF# = C# (chr# i)
+ | otherwise = error "Prelude.chr: bad argument"
unsafeChr :: Int -> Char
unsafeChr (I# i) = C# (chr# i)
ord (C# c) = I# (ord# c)
\end{code}
+String equality is used when desugaring pattern-matches against strings.
+
+\begin{code}
+eqString :: String -> String -> Bool
+eqString = (==)
+\end{code}
%*********************************************************
%* *
zeroInt = I# 0#
oneInt = I# 1#
twoInt = I# 2#
-minInt = I# (-2147483648#) -- GHC <= 2.09 had this at -2147483647
-maxInt = I# 2147483647#
+#if WORD_SIZE_IN_BYTES == 4
+minInt = I# (-0x80000000#)
+maxInt = I# 0x7FFFFFFF#
+#else
+minInt = I# (-0x8000000000000000#)
+maxInt = I# 0x7FFFFFFFFFFFFFFF#
+#endif
instance Eq Int where
- (==) x y = x `eqInt` y
- (/=) x y = x `neInt` y
+ (==) = eqInt
+ (/=) = neInt
instance Ord Int where
- compare x y = compareInt x y
+ compare = compareInt
- (<) x y = ltInt x y
- (<=) x y = leInt x y
- (>=) x y = geInt x y
- (>) x y = gtInt x y
+ (<) = ltInt
+ (<=) = leInt
+ (>=) = geInt
+ (>) = gtInt
compareInt :: Int -> Int -> Ordering
-(I# x) `compareInt` (I# y) | x <# y = LT
- | x ==# y = EQ
- | otherwise = GT
+(I# x) `compareInt` (I# y) = compareInt# x y
+
+compareInt# :: Int# -> Int# -> Ordering
+compareInt# x# y#
+ | x# <# y# = LT
+ | x# ==# y# = EQ
+ | otherwise = GT
\end{code}
-- right-associating infix application operator (useful in continuation-
-- passing style)
+{-# INLINE ($) #-}
($) :: (a -> b) -> a -> b
f $ x = f x
instance CCallable Int
instance CReturnable Int
--- DsCCall knows how to pass strings...
-instance CCallable [Char]
-
instance CReturnable () -- Why, exactly?
\end{code}
%*********************************************************
%* *
+\subsection{Generics}
+%* *
+%*********************************************************
+
+\begin{code}
+data Unit = Unit
+data a :+: b = Inl a | Inr b
+data a :*: b = a :*: b
+\end{code}
+
+
+%*********************************************************
+%* *
\subsection{Numeric primops}
%* *
%*********************************************************
+\begin{code}
+divInt#, modInt# :: Int# -> Int# -> Int#
+x# `divInt#` y#
+ | (x# ># 0#) && (y# <# 0#) = ((x# -# y#) -# 1#) `quotInt#` y#
+ | (x# <# 0#) && (y# ># 0#) = ((x# -# y#) +# 1#) `quotInt#` y#
+ | otherwise = x# `quotInt#` y#
+x# `modInt#` y#
+ | (x# ># 0#) && (y# <# 0#) ||
+ (x# <# 0#) && (y# ># 0#) = if r# /=# 0# then r# +# y# else 0#
+ | otherwise = r#
+ where
+ r# = x# `remInt#` y#
+\end{code}
+
Definitions of the boxed PrimOps; these will be
used in the case of partial applications, etc.
{-# INLINE remInt #-}
{-# INLINE negateInt #-}
-plusInt, minusInt, timesInt, quotInt, remInt, gcdInt :: Int -> Int -> Int
-plusInt (I# x) (I# y) = I# (x +# y)
-minusInt(I# x) (I# y) = I# (x -# y)
-timesInt(I# x) (I# y) = I# (x *# y)
-quotInt (I# x) (I# y) = I# (quotInt# x y)
-remInt (I# x) (I# y) = I# (remInt# x y)
-gcdInt (I# a) (I# b) = I# (gcdInt# a b)
+plusInt, minusInt, timesInt, quotInt, remInt, divInt, modInt, gcdInt :: Int -> Int -> Int
+(I# x) `plusInt` (I# y) = I# (x +# y)
+(I# x) `minusInt` (I# y) = I# (x -# y)
+(I# x) `timesInt` (I# y) = I# (x *# y)
+(I# x) `quotInt` (I# y) = I# (x `quotInt#` y)
+(I# x) `remInt` (I# y) = I# (x `remInt#` y)
+(I# x) `divInt` (I# y) = I# (x `divInt#` y)
+(I# x) `modInt` (I# y) = I# (x `modInt#` y)
+
+gcdInt (I# a) (I# b) = g a b
+ where g 0# 0# = error "PrelBase.gcdInt: gcd 0 0 is undefined"
+ g 0# _ = I# absB
+ g _ 0# = I# absA
+ g _ _ = I# (gcdInt# absA absB)
+
+ absInt x = if x <# 0# then negateInt# x else x
+
+ absA = absInt a
+ absB = absInt b
negateInt :: Int -> Int
-negateInt (I# x) = I# (negateInt# x)
-
-divInt, modInt :: Int -> Int -> Int
-x `divInt` y
- | x > zeroInt && y < zeroInt = quotInt ((x `minusInt` y) `minusInt` oneInt) y
- | x < zeroInt && y > zeroInt = quotInt ((x `minusInt` y) `plusInt` oneInt) y
- | otherwise = quotInt x y
-
-x `modInt` y
- | x > zeroInt && y < zeroInt ||
- x < zeroInt && y > zeroInt = if r/=zeroInt then r `plusInt` y else zeroInt
- | otherwise = r
- where
- r = remInt x y
+negateInt (I# x) = I# (negateInt# x)
gtInt, geInt, eqInt, neInt, ltInt, leInt :: Int -> Int -> Bool
-gtInt (I# x) (I# y) = x ># y
-geInt (I# x) (I# y) = x >=# y
-eqInt (I# x) (I# y) = x ==# y
-neInt (I# x) (I# y) = x /=# y
-ltInt (I# x) (I# y) = x <# y
-leInt (I# x) (I# y) = x <=# y
+(I# x) `gtInt` (I# y) = x ># y
+(I# x) `geInt` (I# y) = x >=# y
+(I# x) `eqInt` (I# y) = x ==# y
+(I# x) `neInt` (I# y) = x /=# y
+(I# x) `ltInt` (I# y) = x <# y
+(I# x) `leInt` (I# y) = x <=# y
+
+{-# RULES
+"int2Word2Int" forall x#. int2Word# (word2Int# x#) = x#
+"word2Int2Word" forall x#. word2Int# (int2Word# x#) = x#
+ #-}
\end{code}
+
+%********************************************************
+%* *
+\subsection{Unpacking C strings}
+%* *
+%********************************************************
+
+This code is needed for virtually all programs, since it's used for
+unpacking the strings of error messages.
+
+\begin{code}
+unpackCString# :: Addr# -> [Char]
+unpackCString# a = unpackCStringList# a
+
+unpackCStringList# :: Addr# -> [Char]
+unpackCStringList# addr
+ = unpack 0#
+ where
+ unpack nh
+ | ch `eqChar#` '\0'# = []
+ | otherwise = C# ch : unpack (nh +# 1#)
+ where
+ ch = indexCharOffAddr# addr nh
+
+unpackAppendCString# :: Addr# -> [Char] -> [Char]
+unpackAppendCString# addr rest
+ = unpack 0#
+ where
+ unpack nh
+ | ch `eqChar#` '\0'# = rest
+ | otherwise = C# ch : unpack (nh +# 1#)
+ where
+ ch = indexCharOffAddr# addr nh
+
+unpackFoldrCString# :: Addr# -> (Char -> a -> a) -> a -> a
+unpackFoldrCString# addr f z
+ = unpack 0#
+ where
+ unpack nh
+ | ch `eqChar#` '\0'# = z
+ | otherwise = C# ch `f` unpack (nh +# 1#)
+ where
+ ch = indexCharOffAddr# addr nh
+
+unpackCStringUtf8# :: Addr# -> [Char]
+unpackCStringUtf8# addr
+ = unpack 0#
+ where
+ unpack nh
+ | ch `eqChar#` '\0'# = []
+ | ch `leChar#` '\x7F'# = C# ch : unpack (nh +# 1#)
+ | ch `leChar#` '\xDF'# =
+ C# (chr# ((ord# ch -# 0xC0#) `iShiftL#` 6# +#
+ (ord# (indexCharOffAddr# addr (nh +# 1#)) -# 0x80#))) :
+ unpack (nh +# 2#)
+ | ch `leChar#` '\xEF'# =
+ C# (chr# ((ord# ch -# 0xE0#) `iShiftL#` 12# +#
+ (ord# (indexCharOffAddr# addr (nh +# 1#)) -# 0x80#) `iShiftL#` 6# +#
+ (ord# (indexCharOffAddr# addr (nh +# 2#)) -# 0x80#))) :
+ unpack (nh +# 3#)
+ | otherwise =
+ C# (chr# ((ord# ch -# 0xF0#) `iShiftL#` 18# +#
+ (ord# (indexCharOffAddr# addr (nh +# 1#)) -# 0x80#) `iShiftL#` 12# +#
+ (ord# (indexCharOffAddr# addr (nh +# 2#)) -# 0x80#) `iShiftL#` 6# +#
+ (ord# (indexCharOffAddr# addr (nh +# 3#)) -# 0x80#))) :
+ unpack (nh +# 4#)
+ where
+ ch = indexCharOffAddr# addr nh
+
+unpackNBytes# :: Addr# -> Int# -> [Char]
+unpackNBytes# _addr 0# = []
+unpackNBytes# addr len# = unpack [] (len# -# 1#)
+ where
+ unpack acc i#
+ | i# <# 0# = acc
+ | otherwise =
+ case indexCharOffAddr# addr i# of
+ ch -> unpack (C# ch : acc) (i# -# 1#)
+
+{-# RULES
+"unpack" forall a . unpackCString# a = build (unpackFoldrCString# a)
+"unpack-list" forall a . unpackFoldrCString# a (:) [] = unpackCStringList# a
+"unpack-append" forall a n . unpackFoldrCString# a (:) n = unpackAppendCString# a n
+
+-- There's a built-in rule (in PrelRules.lhs) for
+-- unpackFoldr "foo" c (unpackFoldr "baz" c n) = unpackFoldr "foobaz" c n
+
+ #-}
+\end{code}
projects / ghc-hetmet.git / blobdiff