[project @ 2005-10-25 09:29:47 by ross]

add Monoid instance

diff --git a/Data/Sequence.hs b/Data/Sequence.hs
index 80c42d3..c68a6ad 100644 (file)
--- a/Data/Sequence.hs
+++ b/Data/Sequence.hs
@@ -81,6 +81,7 @@ import Prelude hiding (
        reverse)
 import qualified Data.List (foldl')
 import Control.Monad (MonadPlus(..), liftM2)
+import Data.Monoid (Monoid(..))
 import Data.FunctorM
 import Data.Typeable
 
@@ -160,6 +161,10 @@ instance Read a => Read (Seq a) where
                return (fromList xs,t)
 #endif
 
+instance Monoid (Seq a) where
+       mempty = empty
+       mappend = (><)
+
 #include "Typeable.h"
 INSTANCE_TYPEABLE1(Seq,seqTc,"Seq")