X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Data%2FMonoid.hs;h=aaefd42169c7bdc85ba028ddd1d1df4aeda4089b;hb=HEAD;hp=a0e3b20eff6b979a84b73f4cd78d1333f4f04f52;hpb=56c20c2ebf7c840e9bc7d81e6497c6d89cb9e88f;p=ghc-base.git

diff --git a/Data/Monoid.hs b/Data/Monoid.hs
index a0e3b20..aaefd42 100644
--- a/Data/Monoid.hs
+++ b/Data/Monoid.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE CPP, NoImplicitPrelude #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Data.Monoid
@@ -30,7 +32,17 @@ module Data.Monoid (
         Last(..)
   ) where
 
+-- Push down the module in the dependency hierarchy.
+#if defined(__GLASGOW_HASKELL__)
+import GHC.Base hiding (Any)
+import GHC.Enum
+import GHC.Num
+import GHC.Read
+import GHC.Show
+import Data.Maybe
+#else
 import Prelude
+#endif
 
 {-
 -- just for testing
@@ -40,7 +52,17 @@ import Test.QuickCheck
 
 -- ---------------------------------------------------------------------------
 -- | The class of monoids (types with an associative binary operation that
--- has an identity).  The method names refer to the monoid of lists,
+-- has an identity).  Instances should satisfy the following laws:
+--
+--  * @mappend mempty x = x@
+--
+--  * @mappend x mempty = x@
+--
+--  * @mappend x (mappend y z) = mappend (mappend x y) z@
+--
+--  * @mconcat = 'foldr' mappend mempty@
+--
+-- The method names refer to the monoid of lists under concatenation,
 -- but there are many other instances.
 --
 -- Minimal complete definition: 'mempty' and 'mappend'.