[project @ 2003-11-06 17:09:50 by simonpj]

[ghc-hetmet.git] / ghc / compiler / basicTypes / UniqSupply.lhs

diff --git a/ghc/compiler/basicTypes/UniqSupply.lhs b/ghc/compiler/basicTypes/UniqSupply.lhs
index 4b8a756..6992751 100644 (file)
--- a/ghc/compiler/basicTypes/UniqSupply.lhs
+++ b/ghc/compiler/basicTypes/UniqSupply.lhs
@@ -11,10 +11,11 @@ module UniqSupply (
        uniqFromSupply, uniqsFromSupply,        -- basic ops
 
        UniqSM,         -- type: unique supply monad
-       initUs, thenUs, thenUs_, returnUs, fixUs, getUs, setUs,
+       initUs, initUs_, thenUs, thenUs_, returnUs, fixUs, getUs, withUs,
        getUniqueUs, getUniquesUs,
        mapUs, mapAndUnzipUs, mapAndUnzip3Us,
        thenMaybeUs, mapAccumLUs,
+       lazyThenUs, lazyMapUs,
 
        mkSplitUniqSupply,
        splitUniqSupply
@@ -23,14 +24,9 @@ module UniqSupply (
 #include "HsVersions.h"
 
 import Unique
-import Panic   ( panic )
 
-import GlaExts
-
-#if __GLASGOW_HASKELL__ < 301
-import IOBase          ( IO(..), IOResult(..) )
-#else
-#endif
+import GLAEXTS
+import UNSAFE_IO       ( unsafeInterleaveIO )
 
 w2i x = word2Int# x
 i2w x = int2Word# x
@@ -44,12 +40,6 @@ i2w_s x = (x :: Int#)
 %*                                                                     *
 %************************************************************************
 
-%************************************************************************
-%*                                                                     *
-\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@,
@@ -67,14 +57,17 @@ mkSplitUniqSupply :: Char -> IO UniqSupply
 
 splitUniqSupply :: UniqSupply -> (UniqSupply, UniqSupply)
 uniqFromSupply  :: UniqSupply -> Unique
-uniqsFromSupply :: Int -> 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
@@ -86,22 +79,19 @@ mkSplitUniqSupply (C# c#)
                return (MkSplitUniqSupply uniq s1 s2)
            )
 
-       mk_unique = _ccall_ genSymZh            >>= \ (W# u#) ->
+       mk_unique = genSymZh            >>= \ (W# u#) ->
                    return (I# (w2i (mask# `or#` u#)))
     in
     mk_supply#
 
+foreign import ccall "genSymZh" unsafe genSymZh :: IO Word
+
 splitUniqSupply (MkSplitUniqSupply _ s1 s2) = (s1, s2)
 \end{code}
 
 \begin{code}
-uniqFromSupply (MkSplitUniqSupply (I# n) _ _) = mkUniqueGrimily n
-
-uniqsFromSupply (I# i) supply = i `get_from` supply
-  where
-    get_from 0# _ = []
-    get_from n (MkSplitUniqSupply (I# u) _ s2)
-      = mkUniqueGrimily u : get_from (n -# 1#) s2
+uniqFromSupply  (MkSplitUniqSupply n _ _)  = mkUniqueGrimily n
+uniqsFromSupply (MkSplitUniqSupply n _ s2) = mkUniqueGrimily n : uniqsFromSupply s2
 \end{code}
 
 %************************************************************************
@@ -113,13 +103,15 @@ uniqsFromSupply (I# i) supply = i `get_from` supply
 \begin{code}
 type UniqSM result = UniqSupply -> (result, UniqSupply)
 
--- the initUs function also returns the final UniqSupply
+-- 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 :: UniqSupply -> UniqSM a -> a
-
-initUs init_us m = case m init_us of { (r,_) -> r }
+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}
@@ -134,37 +126,48 @@ thenUs :: UniqSM a -> (a -> UniqSM b) -> UniqSM b
 thenUs expr cont us
   = 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' }
 
+
 returnUs :: a -> UniqSM a
 returnUs result us = (result, us)
 
+withUs :: (UniqSupply -> (a, UniqSupply)) -> UniqSM a
+withUs f us = f us     -- Ha ha!
+               
 getUs :: UniqSM UniqSupply
-getUs us = (us, panic "getUs: bad supply")
-
-setUs :: UniqSupply -> UniqSM ()
-setUs us old_us = ((), us)
+getUs us = splitUniqSupply us
 
 getUniqueUs :: UniqSM Unique
 getUniqueUs us = case splitUniqSupply us of
                   (us1,us2) -> (uniqFromSupply us1, us2)
 
-getUniquesUs :: Int -> UniqSM [Unique]
-getUniquesUs n us = case splitUniqSupply us of
-                     (us1,us2) -> (uniqsFromSupply n 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])