import Data.Foldable (Foldable())
import Data.Monoid (Monoid)
+#if defined(__GLASGOW_HASKELL__)
+import GHC.Arr
+#elif defined(__HUGS__)
+import Hugs.Array
+#endif
+
-- | Functors representing data structures that can be traversed from
-- left to right.
--
mapM = Prelude.mapM
+#ifndef __NHC__
+instance Ix i => Traversable (Array i) where
+ traverse f arr = listArray (bounds arr) `fmap` traverse f (elems arr)
+#endif
+
-- general functions
-- | 'for' is 'traverse' with its arguments flipped.