Add closure type

Data/Array/Parallel/Base/Closure.hs

+module Data.Array.Parallel.Base.Closure (
+  (:->)(..), closure, ($:)
+) where
+
+infixr 0 :->
+infixr 0 $:
+
+data a :-> b = forall e. Clo !(e -> a -> b) e
+
+closure :: (e -> a -> b) -> e -> (a :-> b)
+closure = Clo
+
+($:) :: (a :-> b) -> a -> b
+Clo f e $: x = f e x
+

ndp.cabal

@@ -12,6 +12,7 @@ exposed-modules:
 	Data.Array.Parallel.Unlifted
         Data.Array.Parallel.Unlifted.Distributed
         Data.Array.Parallel.Unlifted.Parallel
+        Data.Array.Parallel.Base.Closure
 other-modules:
 	Data.Array.Parallel.Base.Config
 	Data.Array.Parallel.Base.Debug

package.conf.in

@@ -5,10 +5,11 @@ maintainer:	ndp@cse.unsw.edu.au
 exposed:	True
 
 exposed-modules:
-	Data.Array.Parallel,
-	Data.Array.Parallel.Unlifted,
+	Data.Array.Parallel
+	Data.Array.Parallel.Unlifted
         Data.Array.Parallel.Unlifted.Distributed
         Data.Array.Parallel.Unlifted.Parallel
+        Data.Array.Parallel.Base.Closure
 
 hidden-modules:
 	Data.Array.Parallel.Base.Config