diff --git a/Data/Bag.hs b/Data/Bag.hs
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+++ b/Data/Bag.hs
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+module Data.Bag where
+import Data.Monoid
+import Data.Foldable
+import Control.Monad
+
+data BagTree a = Leaf a | Branch (BagTree a) (BagTree a) deriving (Show)
+data Bag a = Bag (BagTree a) | Empty deriving (Show)
+
+empty :: Bag a
+empty = Empty
+
+unit :: a -> Bag a
+unit a = Bag $ Leaf a
+
+merge :: Bag a -> Bag a -> Bag a
+merge (Bag a) (Bag b) = Bag $ Branch a b
+merge Empty b = b
+merge a Empty = a
+
+btconcat :: BagTree (BagTree a) -> BagTree a
+btconcat (Leaf a) = a
+btconcat (Branch a b) = Branch (btconcat a) (btconcat b)
+
+bconcat :: Bag (Bag a) -> Bag a
+bconcat Empty = Empty
+bconcat (Bag a) =
+    concat a
+  where
+    concat :: BagTree (Bag a) -> Bag a
+    concat (Leaf x) = x
+    concat (Branch a b) =
+        let a' = concat a
+            b' = concat b in
+                case (a', b') of
+                    (Bag a'', Bag b'') -> Bag $ Branch a'' b''
+                    (Empty, b'') -> b''
+                    (a'', Empty) -> a''
+
+instance Monoid (Bag a) where
+    mempty = empty
+    mappend = merge
+
+instance Foldable BagTree where
+    foldMap f (Leaf x) = f x
+    foldMap f (Branch a b) = (foldMap f a) `mappend` (foldMap f b)
+
+instance Foldable Bag where
+    foldMap _ Empty = mempty
+    foldMap f (Bag t) = foldMap f t
+
+instance Functor BagTree where
+    fmap f (Leaf x) = Leaf $ f x
+    fmap f (Branch a b) = Branch (fmap f a) (fmap f b)
+
+instance Functor Bag where
+    fmap _ Empty = empty
+    fmap f (Bag t) = Bag $ fmap f t
+
+instance Monad BagTree where
+    return = Leaf
+    m >>= f = btconcat $ fmap f m
+
+instance Monad Bag where
+    return = Bag . Leaf
+    m >>= f = bconcat $ fmap f m
+
+instance MonadPlus Bag where
+    mzero = empty
+    mplus = merge
+
+instance Eq a => Eq (BagTree a) where
+    a == b = (toList a) == (toList b)
+
+instance Eq a => Eq (Bag a) where
+    a == b = (toList a) == (toList b)
diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
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+The MIT License (MIT)
+
+Copyright (c) 2011 Daniel Waterworth
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of 
+this software and associated documentation files (the "Software"), to deal in 
+the Software without restriction, including without limitation the rights to 
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 
+of the Software, and to permit persons to whom the Software is furnished to do 
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all 
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
+SOFTWARE.
diff --git a/README b/README
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--- /dev/null
+++ b/README
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+bag provides an alternative to a list for cases where constant time 
+concatenation is required.
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
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+import Distribution.Simple
+main = defaultMain
diff --git a/bag.cabal b/bag.cabal
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--- /dev/null
+++ b/bag.cabal
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+Name:                   bag
+Synopsis:               A simple stable bag.
+Version:                0.1
+Category:               Data Structures
+License:                MIT
+License-file:           LICENSE
+Extra-source-files:     README
+Author:                 Daniel Waterworth <da.waterworth@gmail.com>
+Maintainer:             Daniel Waterworth <da.waterworth@gmail.com>
+Stability:              experimental
+Build-Type:             Simple
+Cabal-Version:          >=1.4
+Description:
+    bag provides an alternative to a list for cases where constant time 
+    concatenation is required.
+
+Library
+    Build-Depends:      base >= 4 && < 5
+    Exposed-modules:
+        Data.Bag