diff --git a/Data/Bifoldable.hs b/Data/Bifoldable.hs
deleted file mode 100644
--- a/Data/Bifoldable.hs
+++ /dev/null
@@ -1,105 +0,0 @@
------------------------------------------------------------------------------
--- |
--- Module      :  Data.Bifoldable
--- Copyright   :  (C) 2011 Edward Kmett,
--- License     :  BSD-style (see the file LICENSE)
---
--- Maintainer  :  Edward Kmett <ekmett@gmail.com>
--- Stability   :  provisional
--- Portability :  portable
---
-----------------------------------------------------------------------------
-module Data.Bifoldable 
-  ( Bifoldable(..)
-  , bifoldr'
-  , bifoldrM
-  , bifoldl'
-  , bifoldlM
-  , bitraverse_
-  , bifor_
-  , bimapM_
-  , biforM_
-  , bisequenceA_
-  , bisequence_
-  , biList
-  , biconcat
-  , biconcatMap
-  , biany
-  , biall
-  ) where
-
-import Control.Applicative
-import Data.Monoid
-
-class Bifoldable p where
-  bifold :: Monoid m => p m m -> m
-  bifold = bifoldMap id id
-
-  bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> p a b -> m
-  bifoldMap f g = bifoldr (mappend . f) (mappend . g) mempty
-
-  bifoldr :: (a -> c -> c) -> (b -> c -> c) -> c -> p a b -> c
-  bifoldr f g z t = appEndo (bifoldMap (Endo . f) (Endo . g) t) z
-
-  bifoldl :: (c -> a -> c) -> (c -> b -> c) -> c -> p a b -> c
-  bifoldl f g z t = appEndo (getDual (bifoldMap (Dual . Endo . flip f) (Dual . Endo . flip g) t)) z
-
-instance Bifoldable (,) where
-  bifoldMap f g (a, b) = f a `mappend` g b
-
-instance Bifoldable Either where
-  bifoldMap f _ (Left a) = f a
-  bifoldMap _ g (Right b) = g b
-
-bifoldr' :: Bifoldable t => (a -> c -> c) -> (b -> c -> c) -> c -> t a b -> c
-bifoldr' f g z0 xs = bifoldl f' g' id xs z0 where 
-  f' k x z = k $! f x z
-  g' k x z = k $! g x z
-
-bifoldrM :: (Bifoldable t, Monad m) => (a -> c -> m c) -> (b -> c -> m c) -> c -> t a b -> m c
-bifoldrM f g z0 xs = bifoldl f' g' return xs z0 where
-  f' k x z = f x z >>= k
-  g' k x z = g x z >>= k
-
-bifoldl':: Bifoldable t => (a -> b -> a) -> (a -> c -> a) -> a -> t b c -> a
-bifoldl' f g z0 xs = bifoldr f' g' id xs z0 where
-  f' x k z = k $! f z x 
-  g' x k z = k $! g z x
-
-bifoldlM :: (Bifoldable t, Monad m) => (a -> b -> m a) -> (a -> c -> m a) -> a -> t b c -> m a 
-bifoldlM f g z0 xs = bifoldr f' g' return xs z0 where
-  f' x k z = f z x >>= k
-  g' x k z = g z x >>= k
-  
-bitraverse_ :: (Bifoldable t, Applicative f) => (a -> f c) -> (b -> f d) -> t a b -> f ()
-bitraverse_ f g = bifoldr ((*>) . f) ((*>) . g) (pure ())
-
-bifor_ :: (Bifoldable t, Applicative f) => t a b -> (a -> f c) -> (b -> f d) -> f ()
-bifor_ t f g = bitraverse_ f g t
-
-bimapM_:: (Bifoldable t, Monad m) => (a -> m c) -> (b -> m d) -> t a b -> m ()
-bimapM_ f g = bifoldr ((>>) . f) ((>>) . g) (return ())
-
-biforM_ :: (Bifoldable t, Monad m) => t a b ->  (a -> m c) -> (b -> m d) -> m ()
-biforM_ t f g = bimapM_ f g t
-
-bisequenceA_ :: (Bifoldable t, Applicative f) => t (f a) (f b) -> f ()
-bisequenceA_ = bifoldr (*>) (*>) (pure ())
-
-bisequence_ :: (Bifoldable t, Monad m) => t (m a) (m b) -> m ()
-bisequence_ = bifoldr (>>) (>>) (return ())
-
-biList :: Bifoldable t => t a a -> [a]
-biList = bifoldr (:) (:) []
-
-biconcat :: Bifoldable t => t [a] [a] -> [a]
-biconcat = bifold
-
-biconcatMap :: Bifoldable t => (a -> [c]) -> (b -> [c]) -> t a b -> [c]
-biconcatMap = bifoldMap 
-
-biany :: Bifoldable t => (a -> Bool) -> (b -> Bool) -> t a b -> Bool
-biany p q = getAny . bifoldMap (Any . p) (Any . q)
-
-biall :: Bifoldable t => (a -> Bool) -> (b -> Bool) -> t a b -> Bool
-biall p q = getAll . bifoldMap (All . p) (All . q)
diff --git a/Data/Bifunctor.hs b/Data/Bifunctor.hs
deleted file mode 100644
--- a/Data/Bifunctor.hs
+++ /dev/null
@@ -1,44 +0,0 @@
------------------------------------------------------------------------------
--- |
--- Module      :  Data.Bifunctor
--- Copyright   :  (C) 2008-2011 Edward Kmett,
--- License     :  BSD-style (see the file LICENSE)
---
--- Maintainer  :  Edward Kmett <ekmett@gmail.com>
--- Stability   :  provisional
--- Portability :  portable
---
-----------------------------------------------------------------------------
-module Data.Bifunctor (Bifunctor(..)) where
-
-import Control.Applicative
-
--- | Minimal definition either 'bimap' or 'first' and 'second'
-class Bifunctor p where
-  bimap :: (a -> b) -> (c -> d) -> p a c -> p b d
-  bimap f g = first f . second g
-
-  first :: (a -> b) -> p a c -> p b c
-  first f = bimap f id
-
-  second :: (b -> c) -> p a b -> p a c
-  second = bimap id 
-
-instance Bifunctor (,) where
-  bimap f g (a, b) = (f a, g b)
-
-instance Bifunctor ((,,) x) where
-  bimap f g (x, a, b) = (x, f a, g b)
-
-instance Bifunctor ((,,,) x y) where
-  bimap f g (x, y, a, b) = (x, y, f a, g b)
-
-instance Bifunctor ((,,,,) x y z) where
-  bimap f g (x, y, z, a, b) = (x, y, z, f a, g b)
-
-instance Bifunctor Either where
-  bimap f _ (Left a) = Left (f a)
-  bimap _ g (Right b) = Right (g b)
-
-instance Bifunctor Const where
-  bimap f _ (Const a) = Const (f a)
diff --git a/Data/Bifunctor/Apply.hs b/Data/Bifunctor/Apply.hs
deleted file mode 100644
--- a/Data/Bifunctor/Apply.hs
+++ /dev/null
@@ -1,55 +0,0 @@
------------------------------------------------------------------------------
--- |
--- Module      :  Data.Bifunctor.Apply
--- Copyright   :  (C) 2011 Edward Kmett,
--- License     :  BSD-style (see the file LICENSE)
---
--- Maintainer  :  Edward Kmett <ekmett@gmail.com>
--- Stability   :  provisional
--- Portability :  portable
---
-----------------------------------------------------------------------------
-module Data.Bifunctor.Apply (
-  -- * Functors
-  -- * BiAppliable bifunctors
-    Biapply(..)
-  , (<<$>>)
-  , (<<..>>)
-  , bilift2
-  , bilift3
-  , module Data.Bifunctor
-  ) where
-
-import Data.Bifunctor
-
-infixl 4 <<$>>, <<.>>, <<., .>>, <<..>>
-
-(<<$>>) :: (a -> b) -> a -> b
-(<<$>>) = id
-
-class Bifunctor p => Biapply p where
-  (<<.>>) :: p (a -> b) (c -> d) -> p a c -> p b d
-
-  -- | a .> b = const id <$> a <.> b
-  (.>>) :: p a b -> p c d -> p c d
-  a .>> b = bimap (const id) (const id) <<$>> a <<.>> b
-
-  -- | a <. b = const <$> a <.> b
-  (<<.) :: p a b -> p c d -> p a b
-  a <<. b = bimap const const <<$>> a <<.>> b
-
-(<<..>>) :: Biapply p => p a c -> p (a -> b) (c -> d) -> p b d
-(<<..>>) = bilift2 (flip id) (flip id)
-
--- | Lift binary functions
-bilift2 :: Biapply w => (a -> b -> c) -> (d -> e -> f) -> w a d -> w b e -> w c f
-bilift2 f g a b = bimap f g <<$>> a <<.>> b
-{-# INLINE bilift2 #-}
-
--- | Lift ternary functions
-bilift3 :: Biapply w => (a -> b -> c -> d) -> (e -> f -> g -> h) -> w a e -> w b f -> w c g -> w d h
-bilift3 f g a b c = bimap f g <<$>> a <<.>> b <<.>> c
-{-# INLINE bilift3 #-}
-
-instance Biapply (,) where
-  (f, g) <<.>> (a, b) = (f a, g b)
diff --git a/Data/Bitraversable.hs b/Data/Bitraversable.hs
deleted file mode 100644
--- a/Data/Bitraversable.hs
+++ /dev/null
@@ -1,102 +0,0 @@
------------------------------------------------------------------------------
--- |
--- Module      :  Data.Bitraversable
--- Copyright   :  (C) 2011 Edward Kmett,
--- License     :  BSD-style (see the file LICENSE)
---
--- Maintainer  :  Edward Kmett <ekmett@gmail.com>
--- Stability   :  provisional
--- Portability :  portable
---
-----------------------------------------------------------------------------
-module Data.Bitraversable
-  ( Bitraversable(..)
-  , bifor
-  , biforM
-  , bimapAccumL
-  , bimapAccumR
-  , bimapDefault
-  , bifoldMapDefault
-  ) where
-
-import Control.Applicative
-import Data.Monoid
-import Data.Bifunctor
-import Data.Bifoldable
-
-class (Bifunctor t, Bifoldable t) => Bitraversable t where
-  bitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> t a b -> f (t c d)
-  bitraverse f g = bisequenceA . bimap f g
-
-  bisequenceA :: Applicative f => t (f a) (f b) -> f (t a b)
-  bisequenceA = bitraverse id id
-
-  bimapM :: Monad m => (a -> m c) -> (b -> m d) -> t a b -> m (t c d)
-  bimapM f g = unwrapMonad . bitraverse (WrapMonad . f) (WrapMonad . g)
-
-  bisequence :: Monad m => t (m a) (m b) -> m (t a b)
-  bisequence = bimapM id id
-
-instance Bitraversable (,) where
-  bitraverse f g (a, b) = (,) <$> f a <*> g b
-
-instance Bitraversable Either where
-  bitraverse f _ (Left a) = Left <$> f a
-  bitraverse _ g (Right b) = Right <$> g b
-
-bifor :: (Bitraversable t, Applicative f) => t a b -> (a -> f c) -> (b -> f d) -> f (t c d)
-bifor t f g = bitraverse f g t
-{-# INLINE bifor #-}
-
-biforM :: (Bitraversable t, Monad m) =>  t a b -> (a -> m c) -> (b -> m d) -> m (t c d)
-biforM t f g = bimapM f g t
-
-
--- left-to-right state transformer
-newtype StateL s a = StateL { runStateL :: s -> (s, a) }
-
-instance Functor (StateL s) where
-        fmap f (StateL k) = StateL $ \ s ->
-                let (s', v) = k s in (s', f v)
-
-instance Applicative (StateL s) where
-        pure x = StateL (\ s -> (s, x))
-        StateL kf <*> StateL kv = StateL $ \ s ->
-                let (s', f) = kf s
-                    (s'', v) = kv s'
-                in (s'', f v)
-
-bimapAccumL :: Bitraversable t => (a -> b -> (a, c)) -> (a -> d -> (a, e)) -> a -> t b d -> (a, t c e)
-bimapAccumL f g s t = runStateL (bitraverse (StateL . flip f) (StateL . flip g) t) s
-
--- right-to-left state transformer
-newtype StateR s a = StateR { runStateR :: s -> (s, a) }
-
-instance Functor (StateR s) where
-        fmap f (StateR k) = StateR $ \ s ->
-                let (s', v) = k s in (s', f v)
-
-instance Applicative (StateR s) where
-        pure x = StateR (\ s -> (s, x))
-        StateR kf <*> StateR kv = StateR $ \ s ->
-                let (s', v) = kv s
-                    (s'', f) = kf s'
-                in (s'', f v)
-
-bimapAccumR :: Bitraversable t => (a -> b -> (a, c)) -> (a -> d -> (a, e)) -> a -> t b d -> (a, t c e)
-bimapAccumR f g s t = runStateR (bitraverse (StateR . flip f) (StateR . flip g) t) s
-
-newtype Id a = Id { getId :: a }
-
-instance Functor Id where
-        fmap f (Id x) = Id (f x)
-
-instance Applicative Id where
-        pure = Id
-        Id f <*> Id x = Id (f x)
-
-bimapDefault :: Bitraversable t => (a -> b) -> (c -> d) -> t a c -> t b d
-bimapDefault f g = getId . bitraverse (Id . f) (Id . g)
-
-bifoldMapDefault :: (Bitraversable t, Monoid m) => (a -> m) -> (b -> m) -> t a b -> m 
-bifoldMapDefault f g = getConst . bitraverse (Const . f) (Const . g)
diff --git a/Data/Semigroup/Bifoldable.hs b/Data/Semigroup/Bifoldable.hs
deleted file mode 100644
--- a/Data/Semigroup/Bifoldable.hs
+++ /dev/null
@@ -1,67 +0,0 @@
------------------------------------------------------------------------------
--- |
--- Module      :  Data.Semigroup.Foldable
--- Copyright   :  (C) 2011 Edward Kmett
--- License     :  BSD-style (see the file LICENSE)
---
--- Maintainer  :  Edward Kmett <ekmett@gmail.com>
--- Stability   :  provisional
--- Portability :  portable
---
-----------------------------------------------------------------------------
-module Data.Semigroup.Bifoldable
-  ( Bifoldable1(..)
-  , bitraverse1_
-  , bifor1_
-  , bisequenceA1_
-  , bifoldMapDefault1
-  ) where
-
-import Prelude hiding (foldr)
-import Data.Bifoldable
-import Data.Functor.Apply
-import Data.Semigroup
-
-class Bifoldable t => Bifoldable1 t where
-  bifold1 :: Semigroup m => t m m -> m
-  bifold1 = bifoldMap1 id id
-
-  bifoldMap1 :: Semigroup m => (a -> m) -> (b -> m) -> t a b -> m
-  bifoldMap1 f g = maybe (error "bifoldMap1") id . getOption . bifoldMap (Option . Just . f) (Option . Just . g)
-
-instance Bifoldable1 Either where
-  bifoldMap1 f _ (Left a) = f a
-  bifoldMap1 _ g (Right b) = g b
-
-instance Bifoldable1 (,) where
-  bifoldMap1 f g (a, b) = f a <> g b
-
-newtype Act f a = Act { getAct :: f a }
-
-instance Apply f => Semigroup (Act f a) where
-  Act a <> Act b = Act (a .> b)
-
-instance Functor f => Functor (Act f) where
-  fmap f (Act a) = Act (f <$> a)
-  b <$ Act a = Act (b <$ a)
-
-bitraverse1_ :: (Bifoldable1 t, Apply f) => (a -> f b) -> (c -> f d) -> t a c -> f ()
-bitraverse1_ f g t = getAct (bifoldMap1 (Act . ignore . f) (Act . ignore . g) t)
-{-# INLINE bitraverse1_ #-}
-
-bifor1_ :: (Bifoldable1 t, Apply f) => t a c -> (a -> f b) -> (c -> f d) -> f ()
-bifor1_ t f g = bitraverse1_ f g t 
-{-# INLINE bifor1_ #-}
-
-ignore :: Functor f => f a -> f ()
-ignore = (() <$)
-
-bisequenceA1_ :: (Bifoldable1 t, Apply f) => t (f a) (f b) -> f ()
-bisequenceA1_ t = getAct (bifoldMap1 (Act . ignore) (Act . ignore) t)
-{-# INLINE bisequenceA1_ #-}
-
--- | Usable default for foldMap, but only if you define bifoldMap1 yourself
-bifoldMapDefault1 :: (Bifoldable1 t, Monoid m) => (a -> m) -> (b -> m) -> t a b -> m
-bifoldMapDefault1 f g = unwrapMonoid . bifoldMap (WrapMonoid . f) (WrapMonoid . g)
-{-# INLINE bifoldMapDefault1 #-}
-
diff --git a/Data/Semigroup/Bitraversable.hs b/Data/Semigroup/Bitraversable.hs
deleted file mode 100644
--- a/Data/Semigroup/Bitraversable.hs
+++ /dev/null
@@ -1,39 +0,0 @@
------------------------------------------------------------------------------
--- |
--- Module      :  Data.Semigroup.Bitraversable
--- Copyright   :  (C) 2011 Edward Kmett
--- License     :  BSD-style (see the file LICENSE)
---
--- Maintainer  :  Edward Kmett <ekmett@gmail.com>
--- Stability   :  provisional
--- Portability :  portable
---
-----------------------------------------------------------------------------
-module Data.Semigroup.Bitraversable
-  ( Bitraversable1(..)
-  , bifoldMap1Default
-  ) where
-
-import Control.Applicative
-import Data.Functor.Apply
-import Data.Semigroup.Bifoldable
-import Data.Bitraversable
-import Data.Bifunctor
-import Data.Semigroup
-
-class (Bifoldable1 t, Bitraversable t) => Bitraversable1 t where
-  bitraverse1 :: Apply f => (a -> f b) -> (c -> f d) -> t a c -> f (t b d)
-  bitraverse1 f g  = bisequence1 . bimap f g
-
-  bisequence1 :: Apply f => t (f a) (f b) -> f (t a b)
-  bisequence1 = bitraverse1 id id
-
-bifoldMap1Default :: (Bitraversable1 t, Semigroup m) => (a -> m) -> (b -> m) -> t a b -> m
-bifoldMap1Default f g = getConst . bitraverse1 (Const . f) (Const . g)
-
-instance Bitraversable1 Either where
-  bitraverse1 f _ (Left a) = Left <$> f a
-  bitraverse1 _ g (Right b) = Right <$> g b
-
-instance Bitraversable1 (,) where
-  bitraverse1 f g (a, b) = (,) <$> f a <.> g b
diff --git a/bifunctors.cabal b/bifunctors.cabal
--- a/bifunctors.cabal
+++ b/bifunctors.cabal
@@ -1,6 +1,6 @@
 name:          bifunctors
 category:      Data, Functors
-version:       0.1.3.3
+version:       3.0
 license:       BSD3
 cabal-version: >= 1.6
 license-file:  LICENSE
@@ -20,10 +20,11 @@
   location: git://github.com/ekmett/bifunctors.git
 
 library
+  hs-source-dirs: src
   build-depends:
-    base          >= 4 && < 5,
+    base          == 4.*,
     semigroups    >= 0.8.3.1 && < 0.9,
-    semigroupoids >= 1.3.1.2 && < 1.4
+    semigroupoids == 3.0.*
 
   exposed-modules:
     Data.Bifunctor
diff --git a/src/Data/Bifoldable.hs b/src/Data/Bifoldable.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Bifoldable.hs
@@ -0,0 +1,105 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Data.Bifoldable
+-- Copyright   :  (C) 2011 Edward Kmett,
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+----------------------------------------------------------------------------
+module Data.Bifoldable 
+  ( Bifoldable(..)
+  , bifoldr'
+  , bifoldrM
+  , bifoldl'
+  , bifoldlM
+  , bitraverse_
+  , bifor_
+  , bimapM_
+  , biforM_
+  , bisequenceA_
+  , bisequence_
+  , biList
+  , biconcat
+  , biconcatMap
+  , biany
+  , biall
+  ) where
+
+import Control.Applicative
+import Data.Monoid
+
+class Bifoldable p where
+  bifold :: Monoid m => p m m -> m
+  bifold = bifoldMap id id
+
+  bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> p a b -> m
+  bifoldMap f g = bifoldr (mappend . f) (mappend . g) mempty
+
+  bifoldr :: (a -> c -> c) -> (b -> c -> c) -> c -> p a b -> c
+  bifoldr f g z t = appEndo (bifoldMap (Endo . f) (Endo . g) t) z
+
+  bifoldl :: (c -> a -> c) -> (c -> b -> c) -> c -> p a b -> c
+  bifoldl f g z t = appEndo (getDual (bifoldMap (Dual . Endo . flip f) (Dual . Endo . flip g) t)) z
+
+instance Bifoldable (,) where
+  bifoldMap f g (a, b) = f a `mappend` g b
+
+instance Bifoldable Either where
+  bifoldMap f _ (Left a) = f a
+  bifoldMap _ g (Right b) = g b
+
+bifoldr' :: Bifoldable t => (a -> c -> c) -> (b -> c -> c) -> c -> t a b -> c
+bifoldr' f g z0 xs = bifoldl f' g' id xs z0 where 
+  f' k x z = k $! f x z
+  g' k x z = k $! g x z
+
+bifoldrM :: (Bifoldable t, Monad m) => (a -> c -> m c) -> (b -> c -> m c) -> c -> t a b -> m c
+bifoldrM f g z0 xs = bifoldl f' g' return xs z0 where
+  f' k x z = f x z >>= k
+  g' k x z = g x z >>= k
+
+bifoldl':: Bifoldable t => (a -> b -> a) -> (a -> c -> a) -> a -> t b c -> a
+bifoldl' f g z0 xs = bifoldr f' g' id xs z0 where
+  f' x k z = k $! f z x 
+  g' x k z = k $! g z x
+
+bifoldlM :: (Bifoldable t, Monad m) => (a -> b -> m a) -> (a -> c -> m a) -> a -> t b c -> m a 
+bifoldlM f g z0 xs = bifoldr f' g' return xs z0 where
+  f' x k z = f z x >>= k
+  g' x k z = g z x >>= k
+  
+bitraverse_ :: (Bifoldable t, Applicative f) => (a -> f c) -> (b -> f d) -> t a b -> f ()
+bitraverse_ f g = bifoldr ((*>) . f) ((*>) . g) (pure ())
+
+bifor_ :: (Bifoldable t, Applicative f) => t a b -> (a -> f c) -> (b -> f d) -> f ()
+bifor_ t f g = bitraverse_ f g t
+
+bimapM_:: (Bifoldable t, Monad m) => (a -> m c) -> (b -> m d) -> t a b -> m ()
+bimapM_ f g = bifoldr ((>>) . f) ((>>) . g) (return ())
+
+biforM_ :: (Bifoldable t, Monad m) => t a b ->  (a -> m c) -> (b -> m d) -> m ()
+biforM_ t f g = bimapM_ f g t
+
+bisequenceA_ :: (Bifoldable t, Applicative f) => t (f a) (f b) -> f ()
+bisequenceA_ = bifoldr (*>) (*>) (pure ())
+
+bisequence_ :: (Bifoldable t, Monad m) => t (m a) (m b) -> m ()
+bisequence_ = bifoldr (>>) (>>) (return ())
+
+biList :: Bifoldable t => t a a -> [a]
+biList = bifoldr (:) (:) []
+
+biconcat :: Bifoldable t => t [a] [a] -> [a]
+biconcat = bifold
+
+biconcatMap :: Bifoldable t => (a -> [c]) -> (b -> [c]) -> t a b -> [c]
+biconcatMap = bifoldMap 
+
+biany :: Bifoldable t => (a -> Bool) -> (b -> Bool) -> t a b -> Bool
+biany p q = getAny . bifoldMap (Any . p) (Any . q)
+
+biall :: Bifoldable t => (a -> Bool) -> (b -> Bool) -> t a b -> Bool
+biall p q = getAll . bifoldMap (All . p) (All . q)
diff --git a/src/Data/Bifunctor.hs b/src/Data/Bifunctor.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Bifunctor.hs
@@ -0,0 +1,44 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Data.Bifunctor
+-- Copyright   :  (C) 2008-2011 Edward Kmett,
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+----------------------------------------------------------------------------
+module Data.Bifunctor (Bifunctor(..)) where
+
+import Control.Applicative
+
+-- | Minimal definition either 'bimap' or 'first' and 'second'
+class Bifunctor p where
+  bimap :: (a -> b) -> (c -> d) -> p a c -> p b d
+  bimap f g = first f . second g
+
+  first :: (a -> b) -> p a c -> p b c
+  first f = bimap f id
+
+  second :: (b -> c) -> p a b -> p a c
+  second = bimap id 
+
+instance Bifunctor (,) where
+  bimap f g (a, b) = (f a, g b)
+
+instance Bifunctor ((,,) x) where
+  bimap f g (x, a, b) = (x, f a, g b)
+
+instance Bifunctor ((,,,) x y) where
+  bimap f g (x, y, a, b) = (x, y, f a, g b)
+
+instance Bifunctor ((,,,,) x y z) where
+  bimap f g (x, y, z, a, b) = (x, y, z, f a, g b)
+
+instance Bifunctor Either where
+  bimap f _ (Left a) = Left (f a)
+  bimap _ g (Right b) = Right (g b)
+
+instance Bifunctor Const where
+  bimap f _ (Const a) = Const (f a)
diff --git a/src/Data/Bifunctor/Apply.hs b/src/Data/Bifunctor/Apply.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Bifunctor/Apply.hs
@@ -0,0 +1,55 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Data.Bifunctor.Apply
+-- Copyright   :  (C) 2011 Edward Kmett,
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+----------------------------------------------------------------------------
+module Data.Bifunctor.Apply (
+  -- * Functors
+  -- * BiAppliable bifunctors
+    Biapply(..)
+  , (<<$>>)
+  , (<<..>>)
+  , bilift2
+  , bilift3
+  , module Data.Bifunctor
+  ) where
+
+import Data.Bifunctor
+
+infixl 4 <<$>>, <<.>>, <<., .>>, <<..>>
+
+(<<$>>) :: (a -> b) -> a -> b
+(<<$>>) = id
+
+class Bifunctor p => Biapply p where
+  (<<.>>) :: p (a -> b) (c -> d) -> p a c -> p b d
+
+  -- | a .> b = const id <$> a <.> b
+  (.>>) :: p a b -> p c d -> p c d
+  a .>> b = bimap (const id) (const id) <<$>> a <<.>> b
+
+  -- | a <. b = const <$> a <.> b
+  (<<.) :: p a b -> p c d -> p a b
+  a <<. b = bimap const const <<$>> a <<.>> b
+
+(<<..>>) :: Biapply p => p a c -> p (a -> b) (c -> d) -> p b d
+(<<..>>) = bilift2 (flip id) (flip id)
+
+-- | Lift binary functions
+bilift2 :: Biapply w => (a -> b -> c) -> (d -> e -> f) -> w a d -> w b e -> w c f
+bilift2 f g a b = bimap f g <<$>> a <<.>> b
+{-# INLINE bilift2 #-}
+
+-- | Lift ternary functions
+bilift3 :: Biapply w => (a -> b -> c -> d) -> (e -> f -> g -> h) -> w a e -> w b f -> w c g -> w d h
+bilift3 f g a b c = bimap f g <<$>> a <<.>> b <<.>> c
+{-# INLINE bilift3 #-}
+
+instance Biapply (,) where
+  (f, g) <<.>> (a, b) = (f a, g b)
diff --git a/src/Data/Bitraversable.hs b/src/Data/Bitraversable.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Bitraversable.hs
@@ -0,0 +1,102 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Data.Bitraversable
+-- Copyright   :  (C) 2011 Edward Kmett,
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+----------------------------------------------------------------------------
+module Data.Bitraversable
+  ( Bitraversable(..)
+  , bifor
+  , biforM
+  , bimapAccumL
+  , bimapAccumR
+  , bimapDefault
+  , bifoldMapDefault
+  ) where
+
+import Control.Applicative
+import Data.Monoid
+import Data.Bifunctor
+import Data.Bifoldable
+
+class (Bifunctor t, Bifoldable t) => Bitraversable t where
+  bitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> t a b -> f (t c d)
+  bitraverse f g = bisequenceA . bimap f g
+
+  bisequenceA :: Applicative f => t (f a) (f b) -> f (t a b)
+  bisequenceA = bitraverse id id
+
+  bimapM :: Monad m => (a -> m c) -> (b -> m d) -> t a b -> m (t c d)
+  bimapM f g = unwrapMonad . bitraverse (WrapMonad . f) (WrapMonad . g)
+
+  bisequence :: Monad m => t (m a) (m b) -> m (t a b)
+  bisequence = bimapM id id
+
+instance Bitraversable (,) where
+  bitraverse f g (a, b) = (,) <$> f a <*> g b
+
+instance Bitraversable Either where
+  bitraverse f _ (Left a) = Left <$> f a
+  bitraverse _ g (Right b) = Right <$> g b
+
+bifor :: (Bitraversable t, Applicative f) => t a b -> (a -> f c) -> (b -> f d) -> f (t c d)
+bifor t f g = bitraverse f g t
+{-# INLINE bifor #-}
+
+biforM :: (Bitraversable t, Monad m) =>  t a b -> (a -> m c) -> (b -> m d) -> m (t c d)
+biforM t f g = bimapM f g t
+
+
+-- left-to-right state transformer
+newtype StateL s a = StateL { runStateL :: s -> (s, a) }
+
+instance Functor (StateL s) where
+        fmap f (StateL k) = StateL $ \ s ->
+                let (s', v) = k s in (s', f v)
+
+instance Applicative (StateL s) where
+        pure x = StateL (\ s -> (s, x))
+        StateL kf <*> StateL kv = StateL $ \ s ->
+                let (s', f) = kf s
+                    (s'', v) = kv s'
+                in (s'', f v)
+
+bimapAccumL :: Bitraversable t => (a -> b -> (a, c)) -> (a -> d -> (a, e)) -> a -> t b d -> (a, t c e)
+bimapAccumL f g s t = runStateL (bitraverse (StateL . flip f) (StateL . flip g) t) s
+
+-- right-to-left state transformer
+newtype StateR s a = StateR { runStateR :: s -> (s, a) }
+
+instance Functor (StateR s) where
+        fmap f (StateR k) = StateR $ \ s ->
+                let (s', v) = k s in (s', f v)
+
+instance Applicative (StateR s) where
+        pure x = StateR (\ s -> (s, x))
+        StateR kf <*> StateR kv = StateR $ \ s ->
+                let (s', v) = kv s
+                    (s'', f) = kf s'
+                in (s'', f v)
+
+bimapAccumR :: Bitraversable t => (a -> b -> (a, c)) -> (a -> d -> (a, e)) -> a -> t b d -> (a, t c e)
+bimapAccumR f g s t = runStateR (bitraverse (StateR . flip f) (StateR . flip g) t) s
+
+newtype Id a = Id { getId :: a }
+
+instance Functor Id where
+        fmap f (Id x) = Id (f x)
+
+instance Applicative Id where
+        pure = Id
+        Id f <*> Id x = Id (f x)
+
+bimapDefault :: Bitraversable t => (a -> b) -> (c -> d) -> t a c -> t b d
+bimapDefault f g = getId . bitraverse (Id . f) (Id . g)
+
+bifoldMapDefault :: (Bitraversable t, Monoid m) => (a -> m) -> (b -> m) -> t a b -> m 
+bifoldMapDefault f g = getConst . bitraverse (Const . f) (Const . g)
diff --git a/src/Data/Semigroup/Bifoldable.hs b/src/Data/Semigroup/Bifoldable.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Semigroup/Bifoldable.hs
@@ -0,0 +1,67 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Data.Semigroup.Foldable
+-- Copyright   :  (C) 2011 Edward Kmett
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+----------------------------------------------------------------------------
+module Data.Semigroup.Bifoldable
+  ( Bifoldable1(..)
+  , bitraverse1_
+  , bifor1_
+  , bisequenceA1_
+  , bifoldMapDefault1
+  ) where
+
+import Prelude hiding (foldr)
+import Data.Bifoldable
+import Data.Functor.Apply
+import Data.Semigroup
+
+class Bifoldable t => Bifoldable1 t where
+  bifold1 :: Semigroup m => t m m -> m
+  bifold1 = bifoldMap1 id id
+
+  bifoldMap1 :: Semigroup m => (a -> m) -> (b -> m) -> t a b -> m
+  bifoldMap1 f g = maybe (error "bifoldMap1") id . getOption . bifoldMap (Option . Just . f) (Option . Just . g)
+
+instance Bifoldable1 Either where
+  bifoldMap1 f _ (Left a) = f a
+  bifoldMap1 _ g (Right b) = g b
+
+instance Bifoldable1 (,) where
+  bifoldMap1 f g (a, b) = f a <> g b
+
+newtype Act f a = Act { getAct :: f a }
+
+instance Apply f => Semigroup (Act f a) where
+  Act a <> Act b = Act (a .> b)
+
+instance Functor f => Functor (Act f) where
+  fmap f (Act a) = Act (f <$> a)
+  b <$ Act a = Act (b <$ a)
+
+bitraverse1_ :: (Bifoldable1 t, Apply f) => (a -> f b) -> (c -> f d) -> t a c -> f ()
+bitraverse1_ f g t = getAct (bifoldMap1 (Act . ignore . f) (Act . ignore . g) t)
+{-# INLINE bitraverse1_ #-}
+
+bifor1_ :: (Bifoldable1 t, Apply f) => t a c -> (a -> f b) -> (c -> f d) -> f ()
+bifor1_ t f g = bitraverse1_ f g t 
+{-# INLINE bifor1_ #-}
+
+ignore :: Functor f => f a -> f ()
+ignore = (() <$)
+
+bisequenceA1_ :: (Bifoldable1 t, Apply f) => t (f a) (f b) -> f ()
+bisequenceA1_ t = getAct (bifoldMap1 (Act . ignore) (Act . ignore) t)
+{-# INLINE bisequenceA1_ #-}
+
+-- | Usable default for foldMap, but only if you define bifoldMap1 yourself
+bifoldMapDefault1 :: (Bifoldable1 t, Monoid m) => (a -> m) -> (b -> m) -> t a b -> m
+bifoldMapDefault1 f g = unwrapMonoid . bifoldMap (WrapMonoid . f) (WrapMonoid . g)
+{-# INLINE bifoldMapDefault1 #-}
+
diff --git a/src/Data/Semigroup/Bitraversable.hs b/src/Data/Semigroup/Bitraversable.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Semigroup/Bitraversable.hs
@@ -0,0 +1,39 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Data.Semigroup.Bitraversable
+-- Copyright   :  (C) 2011 Edward Kmett
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+----------------------------------------------------------------------------
+module Data.Semigroup.Bitraversable
+  ( Bitraversable1(..)
+  , bifoldMap1Default
+  ) where
+
+import Control.Applicative
+import Data.Functor.Apply
+import Data.Semigroup.Bifoldable
+import Data.Bitraversable
+import Data.Bifunctor
+import Data.Semigroup
+
+class (Bifoldable1 t, Bitraversable t) => Bitraversable1 t where
+  bitraverse1 :: Apply f => (a -> f b) -> (c -> f d) -> t a c -> f (t b d)
+  bitraverse1 f g  = bisequence1 . bimap f g
+
+  bisequence1 :: Apply f => t (f a) (f b) -> f (t a b)
+  bisequence1 = bitraverse1 id id
+
+bifoldMap1Default :: (Bitraversable1 t, Semigroup m) => (a -> m) -> (b -> m) -> t a b -> m
+bifoldMap1Default f g = getConst . bitraverse1 (Const . f) (Const . g)
+
+instance Bitraversable1 Either where
+  bitraverse1 f _ (Left a) = Left <$> f a
+  bitraverse1 _ g (Right b) = Right <$> g b
+
+instance Bitraversable1 (,) where
+  bitraverse1 f g (a, b) = (,) <$> f a <.> g b