%
+% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
-\section[UniqSupply]{The @UniqueSupply@ data type and a (monadic) supply thereof}
\begin{code}
module UniqSupply (
lazyThenUs, lazyMapUs,
mkSplitUniqSupply,
- splitUniqSupply
+ splitUniqSupply, listSplitUniqSupply
) where
#include "HsVersions.h"
import Unique
-import GLAEXTS
-import UNSAFE_IO ( unsafeInterleaveIO )
+import GHC.Exts
+import System.IO.Unsafe ( unsafeInterleaveIO )
w2i x = word2Int# x
i2w x = int2Word# x
\begin{code}
data UniqSupply
- = MkSplitUniqSupply Int -- make the Unique with this
+ = MkSplitUniqSupply Int# -- make the Unique with this
UniqSupply UniqSupply
-- when split => these two supplies
\end{code}
mkSplitUniqSupply :: Char -> IO UniqSupply
splitUniqSupply :: UniqSupply -> (UniqSupply, UniqSupply)
+listSplitUniqSupply :: UniqSupply -> [UniqSupply] -- Infinite
uniqFromSupply :: UniqSupply -> Unique
uniqsFromSupply :: UniqSupply -> [Unique] -- Infinite
\end{code}
\begin{code}
mkSplitUniqSupply (C# c#)
= let
-#if __GLASGOW_HASKELL__ >= 503
mask# = (i2w (ord# c#)) `uncheckedShiftL#` (i2w_s 24#)
-#else
- mask# = (i2w (ord# c#)) `shiftL#` (i2w_s 24#)
-#endif
-- here comes THE MAGIC:
-- This is one of the most hammered bits in the whole compiler
mk_supply#
= unsafeInterleaveIO (
- mk_unique >>= \ uniq ->
+ genSymZh >>= \ (I# u#) ->
mk_supply# >>= \ s1 ->
mk_supply# >>= \ s2 ->
- return (MkSplitUniqSupply uniq s1 s2)
+ return (MkSplitUniqSupply (w2i (mask# `or#` (i2w u#))) s1 s2)
)
-
- mk_unique = genSymZh >>= \ (W# u#) ->
- return (I# (w2i (mask# `or#` u#)))
in
mk_supply#
-foreign import ccall unsafe "genSymZh" genSymZh :: IO Word
+foreign import ccall unsafe "genSymZh" genSymZh :: IO Int
splitUniqSupply (MkSplitUniqSupply _ s1 s2) = (s1, s2)
+listSplitUniqSupply (MkSplitUniqSupply _ s1 s2) = s1 : listSplitUniqSupply s2
\end{code}
\begin{code}
-uniqFromSupply (MkSplitUniqSupply n _ _) = mkUniqueGrimily n
-uniqsFromSupply (MkSplitUniqSupply n _ s2) = mkUniqueGrimily n : uniqsFromSupply s2
+uniqFromSupply (MkSplitUniqSupply n _ _) = mkUniqueGrimily (I# n)
+uniqsFromSupply (MkSplitUniqSupply n _ s2) = mkUniqueGrimily (I# n) : uniqsFromSupply s2
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-type UniqSM result = UniqSupply -> (result, UniqSupply)
+newtype UniqSM result = USM { unUSM :: UniqSupply -> (result, UniqSupply) }
+
+instance Monad UniqSM where
+ return = returnUs
+ (>>=) = thenUs
+ (>>) = thenUs_
-- the initUs function also returns the final UniqSupply; initUs_ drops it
initUs :: UniqSupply -> UniqSM a -> (a,UniqSupply)
-initUs init_us m = case m init_us of { (r,us) -> (r,us) }
+initUs init_us m = case unUSM m init_us of { (r,us) -> (r,us) }
initUs_ :: UniqSupply -> UniqSM a -> a
-initUs_ init_us m = case m init_us of { (r,us) -> r }
+initUs_ init_us m = case unUSM m init_us of { (r,us) -> r }
{-# INLINE thenUs #-}
{-# INLINE lazyThenUs #-}
@thenUs@ is where we split the @UniqSupply@.
\begin{code}
fixUs :: (a -> UniqSM a) -> UniqSM a
-fixUs m us
- = (r,us') where (r,us') = m r us
+fixUs m = USM (\us -> let (r,us') = unUSM (m r) us in (r,us'))
thenUs :: UniqSM a -> (a -> UniqSM b) -> UniqSM b
-thenUs expr cont us
- = case (expr us) of { (result, us') -> cont result us' }
+thenUs (USM expr) cont
+ = USM (\us -> case (expr us) of
+ (result, us') -> unUSM (cont result) us')
lazyThenUs :: UniqSM a -> (a -> UniqSM b) -> UniqSM b
-lazyThenUs expr cont us
- = let (result, us') = expr us in cont result us'
+lazyThenUs (USM expr) cont
+ = USM (\us -> let (result, us') = expr us in unUSM (cont result) us')
thenUs_ :: UniqSM a -> UniqSM b -> UniqSM b
-thenUs_ expr cont us
- = case (expr us) of { (_, us') -> cont us' }
+thenUs_ (USM expr) (USM cont)
+ = USM (\us -> case (expr us) of { (_, us') -> cont us' })
returnUs :: a -> UniqSM a
-returnUs result us = (result, us)
+returnUs result = USM (\us -> (result, us))
withUs :: (UniqSupply -> (a, UniqSupply)) -> UniqSM a
-withUs f us = f us -- Ha ha!
+withUs f = USM (\us -> f us) -- Ha ha!
getUs :: UniqSM UniqSupply
-getUs us = splitUniqSupply us
+getUs = USM (\us -> splitUniqSupply us)
getUniqueUs :: UniqSM Unique
-getUniqueUs us = case splitUniqSupply us of
- (us1,us2) -> (uniqFromSupply us1, us2)
+getUniqueUs = USM (\us -> case splitUniqSupply us of
+ (us1,us2) -> (uniqFromSupply us1, us2))
getUniquesUs :: UniqSM [Unique]
-getUniquesUs us = case splitUniqSupply us of
- (us1,us2) -> (uniqsFromSupply us1, us2)
+getUniquesUs = USM (\us -> case splitUniqSupply us of
+ (us1,us2) -> (uniqsFromSupply us1, us2))
\end{code}
\begin{code}