fix nhc98 build: need a qualified Prelude import

[ghc-base.git] / Control / Arrow.hs

diff --git a/Control/Arrow.hs b/Control/Arrow.hs
index a339adf..66c7745 100644 (file)
--- a/Control/Arrow.hs
+++ b/Control/Arrow.hs
@@ -36,11 +36,12 @@ module Control.Arrow (
                ArrowLoop(..)
        ) where
 
-import Prelude
+import Prelude hiding (id,(.))
+import qualified Prelude
 
 import Control.Monad
 import Control.Monad.Fix
-import Control.Compositor
+import Control.Category
 
 infixr 5 <+>
 infixr 3 ***
@@ -55,7 +56,7 @@ infixr 1 ^<<, <<^
 --   as well as 'first'.  The other combinators have sensible
 --   default definitions, which may be overridden for efficiency.
 
-class Compositor a => Arrow a where
+class Category a => Arrow a where
 
        -- | Lift a function to an arrow: you must define either this
        --   or 'pure'.
@@ -96,9 +97,9 @@ class Compositor a => Arrow a where
 
 {-# RULES
 "identity"
-               arr id = identity
+               arr id = id
 "compose/arr"  forall f g .
-               arr f >>> arr g = arr (f >>> g)
+               (arr f) . (arr g) = arr (f . g)
 "first/arr"    forall f .
                first (arr f) = arr (first f)
 "second/arr"   forall f .
@@ -108,9 +109,9 @@ class Compositor a => Arrow a where
 "fanout/arr"   forall f g .
                arr f &&& arr g = arr (f &&& g)
 "compose/first"        forall f g .
-               first f >>> first g = first (f >>> g)
+               (first f) . (first g) = first (f . g)
 "compose/second" forall f g .
-               second f >>> second g = second (f >>> g)
+               (second f) . (second g) = second (f . g)
  #-}
 
 -- Ordinary functions are arrows.
@@ -127,9 +128,9 @@ instance Arrow (->) where
 
 newtype Kleisli m a b = Kleisli { runKleisli :: a -> m b }
 
-instance Monad m => Compositor (Kleisli m) where
-       identity = Kleisli return
-       Kleisli f >>> Kleisli g = Kleisli (\b -> f b >>= g)
+instance Monad m => Category (Kleisli m) where
+       id = Kleisli return
+       (Kleisli f) . (Kleisli g) = Kleisli (\b -> g b >>= f)
 
 instance Monad m => Arrow (Kleisli m) where
        arr f = Kleisli (return . f)