make some Applicative functions into methods, and split off Data.Functor (proposal...

[ghc-base.git] / Data / Traversable.hs

diff --git a/Data/Traversable.hs b/Data/Traversable.hs
index df10679..30aaee6 100644 (file)
--- a/Data/Traversable.hs
+++ b/Data/Traversable.hs
@@ -47,6 +47,8 @@ import Data.Monoid (Monoid)
 import GHC.Arr
 #elif defined(__HUGS__)
 import Hugs.Array
+#elif defined(__NHC__)
+import Array
 #endif
 
 -- | Functors representing data structures that can be traversed from
@@ -101,7 +103,7 @@ class (Functor t, Foldable t) => Traversable t where
 -- instances for Prelude types
 
 instance Traversable Maybe where
-        traverse f Nothing = pure Nothing
+        traverse _ Nothing = pure Nothing
         traverse f (Just x) = Just <$> f x
 
 instance Traversable [] where
@@ -110,10 +112,8 @@ instance Traversable [] where
 
         mapM = Prelude.mapM
 
-#ifndef __NHC__
 instance Ix i => Traversable (Array i) where
-    traverse f arr = listArray (bounds arr) `fmap` traverse f (elems arr)
-#endif
+        traverse f arr = listArray (bounds arr) `fmap` traverse f (elems arr)
 
 -- general functions