[project @ 1998-12-02 13:17:09 by simonm]

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

diff --git a/ghc/compiler/basicTypes/UniqSupply.lhs b/ghc/compiler/basicTypes/UniqSupply.lhs
index 76e5ab3..1ae2133 100644 (file)
--- a/ghc/compiler/basicTypes/UniqSupply.lhs
+++ b/ghc/compiler/basicTypes/UniqSupply.lhs
@@ -1,19 +1,18 @@
 %
-% (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, fixUs,
+       UniqSM,         -- type: unique supply monad
+       initUs, thenUs, thenUs_, returnUs, fixUs, getUs, setUs,
+       getUniqueUs, getUniquesUs,
        mapUs, mapAndUnzipUs, mapAndUnzip3Us,
        thenMaybeUs, mapAccumLUs,
 
@@ -21,17 +20,16 @@ module UniqSupply (
        splitUniqSupply
   ) where
 
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
 
 import Unique
 import Util
 
-import PreludeGlaST
+import GlaExts
 
-#if __GLASGOW_HASKELL__ >= 200
-# define WHASH     GHCbase.W#
+#if __GLASGOW_HASKELL__ < 301
+import IOBase          ( IO(..), IOResult(..) )
 #else
-# define WHASH     W#
 #endif
 
 w2i x = word2Int# x
@@ -68,8 +66,8 @@ data UniqSupply
 mkSplitUniqSupply :: Char -> IO UniqSupply
 
 splitUniqSupply :: UniqSupply -> (UniqSupply, UniqSupply)
-getUnique :: UniqSupply -> Unique
-getUniques :: Int -> UniqSupply -> [Unique]
+uniqFromSupply  :: UniqSupply -> Unique
+uniqsFromSupply :: Int -> UniqSupply -> [Unique]
 \end{code}
 
 \begin{code}
@@ -79,48 +77,31 @@ mkSplitUniqSupply (C# c#)
 
        -- 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 = _ccall_ genSymZh            >>= \ (W# u#) ->
+                   return (I# (w2i (mask# `or#` u#)))
     in
-#if __GLASGOW_HASKELL__ >= 200
-    primIOToIO mk_supply#      >>= \ s ->
-    return s
-#else
-    mk_supply# `thenPrimIO` \ s ->
-    return s
-#endif
+    mk_supply#
 
 splitUniqSupply (MkSplitUniqSupply _ s1 s2) = (s1, s2)
 \end{code}
 
 \begin{code}
-getUnique (MkSplitUniqSupply (I# n) _ _) = mkUniqueGrimily n
+uniqFromSupply (MkSplitUniqSupply (I# n) _ _) = mkUniqueGrimily n
 
-getUniques (I# i) supply = i `get_from` supply
+uniqsFromSupply (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
+      = mkUniqueGrimily u : get_from (n -# 1#) s2
 \end{code}
 
 %************************************************************************
@@ -130,13 +111,13 @@ getUniques (I# i) supply = i `get_from` supply
 %************************************************************************
 
 \begin{code}
-type UniqSM result = UniqSupply -> result
+type UniqSM result = UniqSupply -> (result, UniqSupply)
 
 -- the initUs function also returns the final UniqSupply
 
 initUs :: UniqSupply -> UniqSM a -> a
 
-initUs init_us m = m init_us
+initUs init_us m = case m init_us of { (r,_) -> r }
 
 {-# INLINE thenUs #-}
 {-# INLINE returnUs #-}
@@ -147,20 +128,35 @@ initUs init_us m = m init_us
 \begin{code}
 fixUs :: (a -> UniqSM a) -> UniqSM a
 fixUs m us
-  = r  where  r = m r 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' }
+
+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)
+
+getUs :: UniqSM UniqSupply
+getUs us = (us, panic "getUs: bad supply")
+
+setUs :: UniqSupply -> UniqSM ()
+setUs us old_us = ((), 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)
+\end{code}
+
+\begin{code}
 mapUs :: (a -> UniqSM b) -> [a] -> UniqSM [b]
 
 mapUs f []     = returnUs []