[project @ 2001-03-05 12:18:05 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..a24a4c1 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
@@ -23,8 +24,6 @@ module UniqSupply (
 #include "HsVersions.h"
 
 import Unique
-import Panic   ( panic )
-
 import GlaExts
 
 #if __GLASGOW_HASKELL__ < 301
@@ -113,13 +112,15 @@ uniqsFromSupply (I# i) supply = i `get_from` supply
 \begin{code}
 type UniqSM result = UniqSupply -> (result, UniqSupply)
 
--- the initUs function also returns the final UniqSupply
-
-initUs :: UniqSupply -> UniqSM a -> 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 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}
@@ -134,18 +135,23 @@ 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
@@ -158,13 +164,19 @@ getUniquesUs n us = case splitUniqSupply us of
 
 \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])