%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[UniqSupply]{The @UniqueSupply@ data type and a (monadic) supply thereof}
\begin{code}
-#include "HsVersions.h"
-
module UniqSupply (
UniqSupply, -- Abstractly
- getUnique, getUniques, -- basic ops
+ uniqFromSupply, uniqsFromSupply, -- basic ops
- SYN_IE(UniqSM), -- type: unique supply monad
- initUs, thenUs, returnUs,
+ UniqSM, -- type: unique supply monad
+ initUs, initUs_, thenUs, thenUs_, returnUs, fixUs, getUs, withUs,
+ getUniqueUs, getUniquesUs,
mapUs, mapAndUnzipUs, mapAndUnzip3Us,
thenMaybeUs, mapAccumLUs,
+ lazyThenUs, lazyMapUs,
mkSplitUniqSupply,
splitUniqSupply
) where
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
import Unique
-import Util
-import PreludeGlaST
-
-#if __GLASGOW_HASKELL__ >= 200
-# define WHASH GHCbase.W#
-#else
-# define WHASH W#
-#endif
+import GLAEXTS
+import UNSAFE_IO ( unsafeInterleaveIO )
w2i x = word2Int# x
i2w x = int2Word# x
%* *
%************************************************************************
-%************************************************************************
-%* *
-\subsubsection[UniqSupply-type]{@UniqSupply@ type and operations}
-%* *
-%************************************************************************
-
A value of type @UniqSupply@ is unique, and it can
supply {\em one} distinct @Unique@. Also, from the supply, one can
also manufacture an arbitrary number of further @UniqueSupplies@,
mkSplitUniqSupply :: Char -> IO UniqSupply
splitUniqSupply :: UniqSupply -> (UniqSupply, UniqSupply)
-getUnique :: UniqSupply -> Unique
-getUniques :: Int -> UniqSupply -> [Unique]
+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#
- = unsafeInterleavePrimIO {-unsafe_interleave-} (
- mk_unique `thenPrimIO` \ uniq ->
- mk_supply# `thenPrimIO` \ s1 ->
- mk_supply# `thenPrimIO` \ s2 ->
- returnPrimIO (MkSplitUniqSupply uniq s1 s2)
+ = unsafeInterleaveIO (
+ mk_unique >>= \ uniq ->
+ mk_supply# >>= \ s1 ->
+ mk_supply# >>= \ s2 ->
+ return (MkSplitUniqSupply uniq s1 s2)
)
- where
-{-
- -- inlined copy of unsafeInterleavePrimIO;
- -- this is the single-most-hammered bit of code
- -- in the compiler....
- -- Too bad it's not 1.3-portable...
- unsafe_interleave m s
- = let
- (r, new_s) = m s
- in
- (r, s)
--}
-
- mk_unique = _ccall_ genSymZh `thenPrimIO` \ (WHASH u#) ->
- returnPrimIO (I# (w2i (mask# `or#` u#)))
+
+ mk_unique = genSymZh >>= \ (W# u#) ->
+ return (I# (w2i (mask# `or#` u#)))
in
-#if __GLASGOW_HASKELL__ >= 200
- primIOToIO mk_supply#
-#else
- mk_supply# `thenPrimIO` \ s ->
- return s
-#endif
+ mk_supply#
+
+foreign import ccall "genSymZh" unsafe genSymZh :: IO Word
splitUniqSupply (MkSplitUniqSupply _ s1 s2) = (s1, s2)
\end{code}
\begin{code}
-getUnique (MkSplitUniqSupply (I# n) _ _) = mkUniqueGrimily n
-
-getUniques (I# i) supply = i `get_from` supply
- where
- get_from 0# _ = []
- get_from n (MkSplitUniqSupply (I# u) _ s2)
- = mkUniqueGrimily u : get_from (n `minusInt#` 1#) s2
+uniqFromSupply (MkSplitUniqSupply n _ _) = mkUniqueGrimily n
+uniqsFromSupply (MkSplitUniqSupply n _ s2) = mkUniqueGrimily n : uniqsFromSupply s2
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-type UniqSM result = UniqSupply -> result
-
--- the initUs function also returns the final UniqSupply
+type UniqSM result = UniqSupply -> (result, UniqSupply)
-initUs :: UniqSupply -> UniqSM a -> (UniqSupply, a)
+-- 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 (splitUniqSupply init_us) of { (s1, s2) ->
- (s2, m s1) }
+initUs_ :: UniqSupply -> UniqSM a -> a
+initUs_ init_us m = case m init_us of { (r,us) -> r }
{-# INLINE thenUs #-}
+{-# INLINE lazyThenUs #-}
{-# INLINE returnUs #-}
{-# INLINE splitUniqSupply #-}
\end{code}
@thenUs@ is where we split the @UniqSupply@.
\begin{code}
-thenUs :: UniqSM a -> (a -> UniqSM b) -> UniqSM b
+fixUs :: (a -> UniqSM a) -> UniqSM a
+fixUs m us
+ = (r,us') where (r,us') = m r us
+thenUs :: UniqSM a -> (a -> UniqSM b) -> UniqSM b
thenUs expr cont us
- = case (splitUniqSupply us) of { (s1, s2) ->
- case (expr s1) of { result ->
- cont result s2 }}
-\end{code}
+ = case (expr us) of { (result, us') -> cont result us' }
+
+lazyThenUs :: UniqSM a -> (a -> UniqSM b) -> UniqSM b
+lazyThenUs expr cont us
+ = let (result, us') = expr us in cont result us'
+
+thenUs_ :: UniqSM a -> UniqSM b -> UniqSM b
+thenUs_ expr cont us
+ = case (expr us) of { (_, us') -> cont us' }
+
-\begin{code}
returnUs :: a -> UniqSM a
-returnUs result us = result
+returnUs result us = (result, us)
-mapUs :: (a -> UniqSM b) -> [a] -> UniqSM [b]
+withUs :: (UniqSupply -> (a, UniqSupply)) -> UniqSM a
+withUs f us = f us -- Ha ha!
+
+getUs :: UniqSM UniqSupply
+getUs us = splitUniqSupply us
+
+getUniqueUs :: UniqSM Unique
+getUniqueUs us = case splitUniqSupply us of
+ (us1,us2) -> (uniqFromSupply us1, us2)
+
+getUniquesUs :: UniqSM [Unique]
+getUniquesUs us = case splitUniqSupply us of
+ (us1,us2) -> (uniqsFromSupply us1, us2)
+\end{code}
+\begin{code}
+mapUs :: (a -> UniqSM b) -> [a] -> UniqSM [b]
mapUs f [] = returnUs []
mapUs f (x:xs)
= f x `thenUs` \ r ->
mapUs f xs `thenUs` \ rs ->
returnUs (r:rs)
+lazyMapUs :: (a -> UniqSM b) -> [a] -> UniqSM [b]
+lazyMapUs f [] = returnUs []
+lazyMapUs f (x:xs)
+ = f x `lazyThenUs` \ r ->
+ lazyMapUs f xs `lazyThenUs` \ rs ->
+ returnUs (r:rs)
+
mapAndUnzipUs :: (a -> UniqSM (b,c)) -> [a] -> UniqSM ([b],[c])
mapAndUnzip3Us :: (a -> UniqSM (b,c,d)) -> [a] -> UniqSM ([b],[c],[d])
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