From c853c617d1b305baa4e7779ed436ec4fae84cedb Mon Sep 17 00:00:00 2001
From: simonm <unknown>
Date: Wed, 17 Dec 1997 11:21:44 +0000
Subject: [PATCH] [project @ 1997-12-17 11:21:44 by simonm] Add runST.
---
ghc/lib/glaExts/LazyST.lhs | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/ghc/lib/glaExts/LazyST.lhs b/ghc/lib/glaExts/LazyST.lhs
index 3d457cad3c0d..d18b71608e90 100644
--- a/ghc/lib/glaExts/LazyST.lhs
+++ b/ghc/lib/glaExts/LazyST.lhs
@@ -12,6 +12,7 @@ module LazyST (
ST,
+ runST,
unsafeInterleaveST,
-- ST is one, so you'll likely need some Monad bits
@@ -35,6 +36,7 @@ import qualified UnsafeST ( unsafeInterleaveST )
import PrelBase ( Eq(..), Int, Bool, ($), ()(..) )
import Monad
import Ix
+import GHC
newtype ST s a = ST (STBase.State s -> (a,STBase.State s))
@@ -50,6 +52,10 @@ instance Monad (ST s) where
ST k_a = k r
in
k_a new_s
+
+-- ToDo: un-inline this, it could cause problems...
+runST :: (All s => ST s a) -> a
+runST st = case st of ST st -> let (r,_) = st (STBase.S# realWorld#) in r
\end{code}
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--
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