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+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995
+%
+\section[LiftMonad]{A lifting monad}
+
+\begin{code}
+#if defined(__GLASGOW_HASKELL__)
+module LiftMonad where { bogusLiftMonadThing = True }
+
+#else
+module LiftMonad (
+	LiftM,	-- abstract
+	thenLft, returnLft, mapLft
+    ) where
+
+infixr 9 `thenLft`
+
+data LiftM a = MkLiftM a
+	-- Just add a bottom element under the domain
+\end{code}
+
+Notice that @thenLft@ is strict in its first argument.
+
+\begin{code}
+thenLft :: LiftM a -> (a -> b) -> b
+(MkLiftM x) `thenLft` cont = cont x
+
+returnLft :: a -> LiftM a
+returnLft a = MkLiftM a
+
+mapLft :: (a -> LiftM b) -> [a] -> LiftM [b]
+mapLft f []  	 = returnLft []
+mapLft f (x:xs)
+  = f x		  `thenLft` \ x2 ->
+    mapLft f xs   `thenLft` \ xs2 ->
+    returnLft (x2 : xs2)
+
+#endif
+\end{code}