View patterns, record wildcards, and record puns

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

diff --git a/compiler/basicTypes/UniqSupply.lhs b/compiler/basicTypes/UniqSupply.lhs
index 424dbe2..c228eeb 100644 (file)
--- a/compiler/basicTypes/UniqSupply.lhs
+++ b/compiler/basicTypes/UniqSupply.lhs
@@ -4,6 +4,13 @@
 %
 
 \begin{code}
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
 module UniqSupply (
 
        UniqSupply,             -- Abstractly
@@ -18,7 +25,7 @@ module UniqSupply (
        lazyThenUs, lazyMapUs,
 
        mkSplitUniqSupply,
-       splitUniqSupply
+       splitUniqSupply, listSplitUniqSupply
   ) where
 
 #include "HsVersions.h"
@@ -28,6 +35,13 @@ import Unique
 import GHC.Exts
 import System.IO.Unsafe        ( unsafeInterleaveIO )
 
+#if __GLASGOW_HASKELL__ >= 607
+import GHC.IOBase (unsafeDupableInterleaveIO)
+#else
+unsafeDupableInterleaveIO :: IO a -> IO a
+unsafeDupableInterleaveIO = unsafeInterleaveIO
+#endif
+
 w2i x = word2Int# x
 i2w x = int2Word# x
 i2w_s x = (x :: Int#)
@@ -56,6 +70,7 @@ data UniqSupply
 mkSplitUniqSupply :: Char -> IO UniqSupply
 
 splitUniqSupply :: UniqSupply -> (UniqSupply, UniqSupply)
+listSplitUniqSupply :: UniqSupply -> [UniqSupply]   -- Infinite
 uniqFromSupply  :: UniqSupply -> Unique
 uniqsFromSupply :: UniqSupply -> [Unique]      -- Infinite
 \end{code}
@@ -68,7 +83,7 @@ mkSplitUniqSupply (C# c#)
 
        -- This is one of the most hammered bits in the whole compiler
        mk_supply#
-         = unsafeInterleaveIO (
+         = unsafeDupableInterleaveIO (
                genSymZh    >>= \ (I# u#) ->
                mk_supply#  >>= \ s1 ->
                mk_supply#  >>= \ s2 ->
@@ -80,6 +95,7 @@ mkSplitUniqSupply (C# c#)
 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}