||___|| ||__|| ||__|| __|| Copyright (c) 1994-1999
||---|| ___|| World Wide Web: http://haskell.org/hugs
|| || Report bugs to: hugs-bugs@haskell.org
-|| || Version: January 1999 _______________________________________________
+|| || Version: STG Hugs _______________________________________________
This is the Hugs 98 Standard Prelude, based very closely on the Standard
Prelude for Haskell 98.
-- module Ratio,
Ratio, Rational, (%), numerator, denominator, approxRational,
-- Non-standard exports
- IO(..), IOResult(..), Addr, StablePtr,
+ IO, IOResult(..), Addr, StablePtr,
makeStablePtr, freeStablePtr, deRefStablePtr,
Bool(False, True),
Real(toRational),
-- Integral(quot, rem, div, mod, quotRem, divMod, toInteger),
Integral(quot, rem, div, mod, quotRem, divMod, even, odd, toInteger, toInt),
--- Fractional((/), recip, fromRational),
- Fractional((/), recip, fromRational, fromDouble),
+ Fractional((/), recip, fromRational), fromDouble,
Floating(pi, exp, log, sqrt, (**), logBase, sin, cos, tan,
asin, acos, atan, sinh, cosh, tanh, asinh, acosh, atanh),
RealFrac(properFraction, truncate, round, ceiling, floor),
asTypeOf, error, undefined,
seq, ($!)
- , MVar, newEmptyMVar, newMVar, putMVar, takeMVar, readMVar, swapMVar
- , ThreadId, forkIO
- ,trace
-
- , STRef, newSTRef, readSTRef, writeSTRef
- , IORef, newIORef, readIORef, writeIORef
-
- -- This lot really shouldn't be exported, but are needed to
- -- implement various libs.
- ,primCompAux,PrimArray,primRunST,primNewArray,primWriteArray
- ,primUnsafeFreezeArray,primIndexArray,primGetRawArgs,primGetEnv
- ,nh_stdin,nh_stdout,nh_stderr,copy_String_to_cstring,nh_open
- ,nh_free,nh_close,nh_errno,nh_flush,nh_read,primIntToChar
- ,unsafeInterleaveIO,nh_write,primCharToInt,
- nullAddr, incAddr, isNullAddr,
- nh_filesize, nh_iseof, nh_system, nh_exitwith, nh_getPID,
- nh_getCPUtime, nh_getCPUprec, prelCleanupAfterRunAction,
-
- Word,
- primGtWord, primGeWord, primEqWord, primNeWord,
- primLtWord, primLeWord, primMinWord, primMaxWord,
- primPlusWord, primMinusWord, primTimesWord, primQuotWord,
- primRemWord, primQuotRemWord, primNegateWord, primAndWord,
- primOrWord, primXorWord, primNotWord, primShiftLWord,
- primShiftRAWord, primShiftRLWord, primIntToWord, primWordToInt,
-
- primAndInt, primOrInt, primXorInt, primNotInt,
- primShiftLInt, primShiftRAInt, primShiftRLInt,
-
- primAddrToInt, primIntToAddr,
-
- primDoubleToFloat, primFloatToDouble,
-
) where
-- Standard value bindings {Prelude} ----------------------------------------
(/) :: a -> a -> a
recip :: a -> a
fromRational :: Rational -> a
- fromDouble :: Double -> a
-- Minimal complete definition: fromRational and ((/) or recip)
recip x = 1 / x
- fromDouble = fromRational . toRational
x / y = x * recip y
+fromDouble :: Fractional a => Double -> a
+fromDouble n = fromRational (toRational n)
class (Fractional a) => Floating a where
pi :: a
compare [] (_:_) = LT
compare [] [] = EQ
compare (_:_) [] = GT
- compare (x:xs) (y:ys) = primCompAux x y (compare xs ys)
+ compare (x:xs) (y:ys) = hugsprimCompAux x y (compare xs ys)
instance Functor [] where
fmap = map
instance Fractional Float where
(/) = primDivideFloat
fromRational = rationalToRealFloat
- fromDouble = primDoubleToFloat
-
instance Fractional Double where
(/) = primDivideDouble
fromRational = rationalToRealFloat
- fromDouble x = x
rationalToRealFloat x = x'
where x' = f e
(x:%y) / (x':%y') = (x*y') % (y*x')
recip (x:%y) = if x < 0 then (-y) :% (-x) else y :% x
fromRational (x:%y) = fromInteger x :% fromInteger y
- fromDouble = doubleToRatio
-- Hugs optimises code of the form fromRational (doubleToRatio x)
doubleToRatio :: Integral a => Double -> Ratio a
showParen :: Bool -> ShowS -> ShowS
showParen b p = if b then showChar '(' . p . showChar ')' else p
-showField :: Show a => String -> a -> ShowS
-showField m v = showString m . showChar '=' . shows v
+hugsprimShowField :: Show a => String -> a -> ShowS
+hugsprimShowField m v = showString m . showChar '=' . shows v
readParen :: Bool -> ReadS a -> ReadS a
readParen b g = if b then mandatory else optional
(")",u) <- lex t ]
-readField :: Read a => String -> ReadS a
-readField m s0 = [ r | (t, s1) <- lex s0, t == m,
- ("=",s2) <- lex s1,
- r <- reads s2 ]
+hugsprimReadField :: Read a => String -> ReadS a
+hugsprimReadField m s0 = [ r | (t, s1) <- lex s0, t == m,
+ ("=",s2) <- lex s1,
+ r <- reads s2 ]
lex :: ReadS String
lex "" = [("","")]
-- Hooks for primitives: -----------------------------------------------------
-- Do not mess with these!
-primCompAux :: Ord a => a -> a -> Ordering -> Ordering
-primCompAux x y o = case compare x y of EQ -> o; LT -> LT; GT -> GT
+hugsprimCompAux :: Ord a => a -> a -> Ordering -> Ordering
+hugsprimCompAux x y o = case compare x y of EQ -> o; LT -> LT; GT -> GT
+
+hugsprimEqChar :: Char -> Char -> Bool
+hugsprimEqChar c1 c2 = primEqChar c1 c2
hugsprimPmInt :: Num a => Int -> a -> Bool
hugsprimPmInt n x = fromInt n == x
hugsprimPmInteger :: Num a => Integer -> a -> Bool
hugsprimPmInteger n x = fromInteger n == x
-primPmDouble :: Fractional a => Double -> a -> Bool
-primPmDouble n x = fromDouble n == x
+hugsprimPmDouble :: Fractional a => Double -> a -> Bool
+hugsprimPmDouble n x = fromDouble n == x
-- ToDo: make the message more informative.
-primPmFail :: a
-primPmFail = error "Pattern Match Failure"
+hugsprimPmFail :: a
+hugsprimPmFail = error "Pattern Match Failure"
-- used in desugaring Foreign functions
+-- Note: hugsprimMkIO is used as a wrapper to translate a Hugs-created
+-- bit of code of type RealWorld -> (a,RealWorld) into a proper IO value.
+-- What follows is the version for standalone mode. ghc/lib/std/PrelHugs.lhs
+-- contains a version used in combined mode. That version takes care of
+-- switching between the GHC and Hugs IO representations, which are different.
hugsprimMkIO :: (RealWorld -> (a,RealWorld)) -> IO a
-hugsprimMkIO = ST
+hugsprimMkIO = IO
hugsprimCreateAdjThunk :: (a -> b) -> String -> Char -> IO Addr
hugsprimCreateAdjThunk fun typestr callconv
--
-- ToDo: change this (and Hugs code generator) to use ByteArrays
-primUnpackString :: Addr -> String
-primUnpackString a = unpack 0
+hugsprimUnpackString :: Addr -> String
+hugsprimUnpackString a = unpack 0
where
-- The following decoding is based on evalString in the old machine.c
unpack i
catch :: IO a -> (IOError -> IO a) -> IO a
catch m k
- = ST (\s -> unST m s `primCatch` \ err -> unST (k (e2ioe err)) s)
+ = IO (\s -> unIO m s `primCatch` \ err -> unIO (k (e2ioe err)) s)
where
e2ioe (IOExcept s) = IOError s
e2ioe other = IOError (show other)
print = putStrLn . show
getChar :: IO Char
-getChar = unsafeInterleaveIO (
- nh_stdin >>= \h ->
+getChar = nh_stdin >>= \h ->
nh_read h >>= \ci ->
return (primIntToChar ci)
- )
getLine :: IO String
getLine = do c <- getChar
nh_getenv ptr >>= \ptr2 ->
nh_free ptr >>
if isNullAddr ptr2
- then return []
+ then ioError (IOError "getEnv failed")
else
copy_cstring_to_String ptr2 >>= \result ->
return result
------------------------------------------------------------------------------
--- ST, IO --------------------------------------------------------------------
+-- ST ------------------------------------------------------------------------
------------------------------------------------------------------------------
newtype ST s a = ST (s -> (a,s))
-
+unST (ST a) = a
data RealWorld
-type IO a = ST RealWorld a
---primRunST :: (forall s. ST s a) -> a
-primRunST :: ST RealWorld a -> a
-primRunST m = fst (unST m theWorld)
+runST :: (__forall s . ST s a) -> a
+runST m = fst (unST m alpha)
where
- theWorld :: RealWorld
- theWorld = error "primRunST: entered the RealWorld"
+ alpha = error "runST: entered the RealWorld"
-unST (ST a) = a
+fixST :: (a -> ST s a) -> ST s a
+fixST m = ST (\ s ->
+ let
+ (r,s) = unST (m r) s
+ in
+ (r,s))
instance Functor (ST s) where
fmap f x = x >>= (return . f)
return x = ST (\s -> (x,s))
m >>= k = ST (\s -> case unST m s of { (a,s') -> unST (k a) s' })
+unsafeInterleaveST :: ST s a -> ST s a
+unsafeInterleaveST m = ST (\ s -> (fst (unST m s), s))
+
+------------------------------------------------------------------------------
+-- IO ------------------------------------------------------------------------
+------------------------------------------------------------------------------
+
+newtype IO a = IO (RealWorld -> (a,RealWorld))
+unIO (IO a) = a
+
+stToIO :: ST RealWorld a -> IO a
+stToIO (ST fn) = IO fn
+
+ioToST :: IO a -> ST RealWorld a
+ioToST (IO fn) = ST fn
+
+unsafePerformIO :: IO a -> a
+unsafePerformIO m = fst (unIO m theWorld)
+ where
+ theWorld :: RealWorld
+ theWorld = error "unsafePerformIO: entered the RealWorld"
+
+instance Functor IO where
+ fmap f x = x >>= (return . f)
+
+instance Monad IO where
+ m >> k = IO (\s -> case unIO m s of { (a,s') -> unIO k s' })
+ return x = IO (\s -> (x,s))
+ m >>= k = IO (\s -> case unIO m s of { (a,s') -> unIO (k a) s' })
-- Library IO has a global variable which accumulates Handles
-- as they are opened. We keep here a second global variable
-- Doing it like this means the Prelude does not have to know
-- anything about the grotty details of the Handle implementation.
prelCleanupAfterRunAction :: IORef (Maybe (IO ()))
-prelCleanupAfterRunAction = primRunST (newIORef Nothing)
+prelCleanupAfterRunAction = unsafePerformIO (newIORef Nothing)
-- used when Hugs invokes top level function
hugsprimRunIO_toplevel :: IO a -> ()
hugsprimRunIO_toplevel m
- = protect 5 (fst (unST composite_action realWorld))
+ = protect 5 (fst (unIO composite_action realWorld))
where
composite_action
= do writeIORef prelCleanupAfterRunAction Nothing
= comp
protect n comp
= primCatch (protect (n-1) comp)
- (\e -> fst (unST (putStr (show e ++ "\n")) realWorld))
-
-trace, trace_quiet :: String -> a -> a
-trace s x
- = trace_quiet ("trace: " ++ s) x
-trace_quiet s x
- = (primRunST (putStr (s ++ "\n"))) `seq` x
-
-unsafeInterleaveST :: ST s a -> ST s a
-unsafeInterleaveST m = ST (\ s -> (fst (unST m s), s))
+ (\e -> fst (unIO (putStr (show e ++ "\n")) realWorld))
unsafeInterleaveIO :: IO a -> IO a
-unsafeInterleaveIO = unsafeInterleaveST
-
+unsafeInterleaveIO m = IO (\ s -> (fst (unIO m s), s))
------------------------------------------------------------------------------
-- Word, Addr, StablePtr, Prim*Array -----------------------------------------
writeSTRef :: STRef s a -> a -> ST s ()
writeSTRef = primWriteRef
-type IORef a = STRef RealWorld a
+newtype IORef a = IORef (STRef RealWorld a)
newIORef :: a -> IO (IORef a)
-newIORef = primNewRef
+newIORef a = stToIO (primNewRef a >>= \ ref ->return (IORef ref))
readIORef :: IORef a -> IO a
-readIORef = primReadRef
+readIORef (IORef ref) = stToIO (primReadRef ref)
writeIORef :: IORef a -> a -> IO ()
-writeIORef = primWriteRef
+writeIORef (IORef ref) a = stToIO (primWriteRef ref a)
------------------------------------------------------------------------------
takeMVar :: MVar a -> IO a
takeMVar m
- = ST (\world -> primTakeMVar m cont world)
+ = IO (\world -> primTakeMVar m cont world)
where
-- cont :: a -> RealWorld -> (a,RealWorld)
-- where 'a' is as in the top-level signature
forkIO :: IO a -> IO ThreadId
-- Simple version; doesn't catch exceptions in computation
-- forkIO computation
--- = primForkIO (primRunST computation)
+-- = primForkIO (unsafePerformIO computation)
forkIO computation
= primForkIO (
primCatch
- (unST computation realWorld `primSeq` ())
+ (unIO computation realWorld `primSeq` ())
(\e -> trace_quiet ("forkIO: uncaught exception: " ++ show e) ())
)
where
realWorld = error "primForkIO: entered the RealWorld"
+trace_quiet s x
+ = (unsafePerformIO (putStr (s ++ "\n"))) `seq` x
-- showFloat ------------------------------------------------------------------
projects / ghc-hetmet.git / blobdiff