diff --git a/ConcurrentUtils.cabal b/ConcurrentUtils.cabal
new file mode 100644
--- /dev/null
+++ b/ConcurrentUtils.cabal
@@ -0,0 +1,21 @@
+-- Initial FChan.cabal generated by cabal init.  For further documentation,
+--  see http://haskell.org/cabal/users-guide/
+
+name:                ConcurrentUtils
+version:             0.2.0.0
+synopsis:            Concurrent utilities
+-- description:         
+homepage:            alkalisoftware.net
+license:             GPL-2
+license-file:        LICENSE
+author:              James Candy
+maintainer:          info@alkalisoftware.net
+-- copyright:           
+category:            Concurrency
+build-type:          Simple
+cabal-version:       >=1.8
+
+library
+  exposed-modules:     Control.Concurrent.FChan, Control.Concurrent.Processes, Control.Concurrent.AList, Control.Concurrent.Deadlock, Control.Concurrent.DataParallel, Control.Concurrent.Conc
+  -- other-modules:
+  build-depends:     base >= 2 && <= 4, containers >= 0.4.0.0, array >= 0.3.0.3, parallel
diff --git a/Control/Concurrent/AList.hs b/Control/Concurrent/AList.hs
new file mode 100644
--- /dev/null
+++ b/Control/Concurrent/AList.hs
@@ -0,0 +1,66 @@
+module Control.Concurrent.AList (AList(..), filterAList, assocFold, monoid, lenAList, findAList, concatAList) where
+
+import Control.Parallel
+import Control.Monad
+import Control.Applicative
+import Data.Monoid
+import Data.Foldable (Foldable, foldMap)
+import Data.Traversable (Traversable, traverse, foldMapDefault)
+
+-- | Lists suitable for parallel execution (taken from Hackage's monad-par package). (For converting to regular lists, there is the toList function in Data.Foldable.)
+data AList t = Append (AList t) (AList t) | List [t] deriving (Eq, Ord, Show)
+
+instance Monad AList where
+	return x = List [x]
+	Append ls ls2 >>= f = ((ls >>= f) `par` (ls2 >>= f)) `seq` Append (ls >>= f) (ls2 >>= f)
+	List ls >>= f = foldr mplus mzero (map f ls)
+
+instance MonadPlus AList where
+	mzero = List []
+	mplus m n = (m `par` n) `seq` case (m, n) of
+		(List [x], List xs) -> List (x:xs)
+		(List [x], Append y z) -> Append (mplus m y) z
+		(List [], n) -> n
+		(m, List []) -> m
+		_ -> Append m n
+
+instance Functor AList where
+	fmap f m = m >>= return . f
+
+instance Traversable AList where
+	traverse f (Append ls ls2) = Append <$> traverse f ls <*> traverse f ls2
+	traverse f (List ls) = List <$> traverse f ls
+
+instance Foldable AList where
+	foldMap = foldMapDefault
+
+-- | Filters the AList using a predicate.
+filterAList f ls = ls >>= \x -> List $ if f x then [x] else []
+
+noNils (Append m n) = noNils m `mplus` noNils n
+noNils ls = ls
+
+assocFold0 f (Append ls ls2) = (assocFold0 f ls `par` assocFold0 f ls2) `seq` f (assocFold0 f ls) (assocFold0 f ls2)
+assocFold0 f (List ls) = foldl1 f ls
+
+-- | Folds the AList with a function, that must be associative. This allows parallelism to be introduced.
+assocFold f = assocFold0 f . noNils
+
+-- | Combine monoid elements to get a result.
+monoid ls = if noNils ls == List [] then
+		mempty
+	else
+		assocFold mappend ls
+
+-- | Length of an AList.
+lenAList ls = if noNils ls == List [] then
+		0
+	else
+		assocFold (+) (fmap (const 1) ls)
+
+-- | Find the first element satisfying a predicate.
+findAList f = getFirst . monoid . fmap (\x -> First $ if f x then Just x else Nothing)
+
+-- | Concatenate an AList of ALists.
+concatAList ls = ls >>= id
+
diff --git a/Control/Concurrent/Conc.hs b/Control/Concurrent/Conc.hs
new file mode 100644
--- /dev/null
+++ b/Control/Concurrent/Conc.hs
@@ -0,0 +1,130 @@
+{-# LANGUAGE ScopedTypeVariables, DeriveDataTypeable #-}
+-- | A module of concurrent higher order functions.
+module Control.Concurrent.Conc (ExceptionList(..), ConcException(..), assocFold, concF_, conc_, concF, conc, concP, oneOfF, oneOf) where
+
+import Prelude hiding (catch)
+import Control.Exception
+import Data.Typeable
+import Control.Concurrent.QSemN
+import Control.Concurrent.Chan
+import GHC.Conc
+import Data.Array.IO (newArray_, readArray, writeArray, getElems, IOArray)
+import Data.Array
+import Data.Array.MArray
+import Data.IORef
+import Control.Monad
+
+-- |For exceptions caused by caller code.
+data ExceptionList = ExceptionList [SomeException] deriving (Show, Typeable)
+
+instance Exception ExceptionList
+
+-- |For internal errors. If a procedure throws this, some threads it created may still be running. It is thrown separately from ExceptionList.
+data ConcException = ConcException deriving (Show, Typeable)
+
+instance Exception ConcException
+
+simpleConc_ mnds = do
+	sem <- newQSemN 0
+	mapM_ (\m -> forkIO (do
+			m
+			signalQSemN sem 1))
+		mnds
+	waitQSemN sem (length mnds)
+
+divideUp nPieces nVals = zip (0 : divisions) divisions where
+	divisions = if nPieces >= nVals then
+			[1..nVals]
+		else
+			map (`div` nPieces) $ take nPieces $ iterate (nVals +) nVals
+
+getExceptions exs = do
+	writeChan exs Nothing
+	exslst <- let chanToList exslst = do
+					may <- readChan exs
+					case may of
+						Just ex -> case fromException ex of
+							Just (_ :: ConcException) -> throwIO ex
+							Nothing -> chanToList (ex : exslst)
+						Nothing -> return exslst in
+			chanToList []
+	unless (null exslst) $ throwIO (ExceptionList exslst)
+
+-- |Runs an associative folding function on the given list. Note: this function only spawns enough threads to make effective use of the /capabilities/. Any two list elements may be processed sequentially or concurrently. To get parallelism, you have to set the numCapabilities value, e.g. using GHC's +RTS -N flag.
+assocFold :: forall a. (a -> a -> IO a) -> Array Int a -> IO a
+assocFold f parm = do
+	let (lo, hi) = bounds parm
+	when (lo > hi) $ error "Conc.assocFold: empty list"
+	exs <- newChan
+	ar <- (newArray_ (0, (rangeSize (bounds parm) `min` numCapabilities) - 1) :: IO (IOArray Int a))
+	let
+		rtnException ex = writeChan exs (Just ex) >> return undefined
+		innerExHandler m = catch m rtnException
+		outerExHandler m = catch m (\(_ :: SomeException) -> rtnException (toException ConcException)) in
+		outerExHandler $ simpleConc_ $ map (\(i, (x, y)) ->
+			innerExHandler $ foldM f (parm ! x) (map (parm !) [x+1..y]) >>= writeArray ar i) $ zip [0..] (divideUp numCapabilities (rangeSize (bounds parm)))
+	getExceptions exs
+	(x:xs) <- getElems ar
+	foldM f x xs
+
+concF_ :: Int -> (Int -> IO ()) -> IO ()
+concF_ n mnds = do
+	exs <- newChan
+	let
+		rtnException ex = writeChan exs (Just ex) >> return undefined
+		innerExHandler m = catch m rtnException
+		outerExHandler m = catch m (\(_ :: SomeException) -> rtnException (toException ConcException)) in
+		outerExHandler $ simpleConc_ $ map (\(x, y) -> outerExHandler $ simpleConc_ $ map (innerExHandler . mnds) [x..y-1]) $ divideUp numCapabilities n
+	getExceptions exs
+
+partConc_ f mnds = concF_ (rangeSize (bounds mnds)) $ f . (+ fst (bounds mnds))
+
+conc_ mnds = partConc_ (mnds !) mnds
+
+unsafeFreeze' :: IOArray Int e -> IO (Array Int e)
+unsafeFreeze' = freeze
+
+partConcF bnds f mnds = do
+	res <- newArray_ bnds
+	f (\i -> do
+		x <- mnds i
+		writeArray res i x)
+	unsafeFreeze' res
+
+-- |n is the number of computations which are indexed from 0 to n - 1.
+concF n = partConcF (0, n - 1) (concF_ n)
+
+-- |Runs several computations in parallel, and returns their results as an array. Waits for all threads to end before returning.
+conc mnds = partConcF (bounds mnds) (\f -> partConc_ f mnds) (mnds !)
+
+-- |Version of concF specialized for two computations.
+concP m m2 = liftM ((\[Left x, Right y] -> (x, y)) . elems)
+	$ concF 2 (\i -> if i == 0 then
+				liftM Left m
+			else
+				liftM Right m2)
+
+partOneOfF bnds mnds = do
+	thds <- newIORef []
+	chn <- newChan
+	finally (do
+		mapM_ (\n -> do
+			thd <- forkIO (catch (mnds n >>= writeChan chn . Right) (\(ex :: SomeException) -> writeChan chn (Left ex) >> return undefined))
+			modifyIORef thds (thd:))
+			(range bnds)
+		let chanToList n exs = if n == rangeSize bnds then
+				throwIO (ExceptionList exs)
+			else readChan chn >>=
+				either
+					(chanToList (n + 1) . (:exs))
+					return in
+			chanToList 0 [])
+		(catch (readIORef thds >>= mapM_ killThread) (\(_ :: SomeException) -> throwIO ConcException))
+
+oneOfF :: Int -> (Int -> IO a) -> IO a
+oneOfF n = partOneOfF (0, n - 1)
+
+-- |Runs several computations in parallel, and returns one of their results (terminating the other computations).
+oneOf :: Array Int (IO a) -> IO a
+oneOf mnds = partOneOfF (bounds mnds) (mnds !)
+
diff --git a/Control/Concurrent/DataParallel.hs b/Control/Concurrent/DataParallel.hs
new file mode 100644
--- /dev/null
+++ b/Control/Concurrent/DataParallel.hs
@@ -0,0 +1,143 @@
+{-# LANGUAGE GADTs, Rank2Types, StandaloneDeriving #-}
+-- | An implementation of nested data parallelism
+module Control.Concurrent.DataParallel (ArrC, inject, project, newArray, A(Count, Index, Zip, Unzip, Concat, Map, Comp, Arr, Prod, Sum), optimize, eval) where
+
+import Data.Array
+import Data.Tree
+import Control.Category
+import Control.Arrow
+import Control.Monad
+import Control.Concurrent.Conc
+import System.IO.Unsafe
+import Prelude hiding (id, (.))
+
+data ArrC t = ArrC !(Array Int t) !(Forest Int)
+
+inject ar = ArrC ar [Node 0 [], Node (uncurry subtract (bounds ar) + 1) []]
+
+project (ArrC ar _) = ar
+
+instance Functor ArrC where
+	fmap f (ArrC ar ls) = ArrC (fmap f ar) ls
+
+newArray ls = listArray (0, length ls - 1) ls
+
+pairUp ls = zip ls (tail ls)
+
+instance Show (t -> u) where
+	showsPrec _ _ = ("<FUNCTION>"++)
+
+data A t u where
+	-- | Constructors for caller's use
+	Count :: A Int (ArrC Int)
+	Index :: A (ArrC t, Int) t
+	Zip :: A (ArrC t, ArrC u) (ArrC (t, u))
+	Unzip :: A (ArrC (t, u)) (ArrC t, ArrC u)
+	Concat :: A (ArrC (ArrC t)) (ArrC t)
+	Map :: A t u -> A (ArrC t) (ArrC u)
+	Comp :: A u v -> A t u -> A t v
+	Arr :: (t -> u) -> A t u
+	Prod :: A t u -> A v w -> A (t, v) (u, w)
+	Sum :: A t u -> A v w -> A (Either t v) (Either u w)
+
+	-- Internal constructors
+	Pack :: A (ArrC (ArrC t)) (ArrC t)
+	Unpack :: A (ArrC t) (ArrC (ArrC t))
+	PackSum :: A (Either t (ArrC u)) (ArrC (Either t u))
+	UnpackSum :: A (ArrC (Either t u)) (Either t (ArrC u))
+
+mirror ei = either Right Left ei
+
+deriving instance Show (A t u)
+
+instance Category A where
+	id = arr id
+	(.) = Comp
+
+instance Arrow A where
+	arr = Arr
+	(***) = Prod
+	first a = a *** arr id
+	second a = arr id *** a
+
+instance ArrowChoice A where
+	(+++) = Sum
+	left a = a +++ arr id
+	right a = arr id +++ a
+
+reassociate :: A u v -> A t u -> A t v
+reassociate (Comp a a2) = reassociate a . reassociate a2
+reassociate x = (x .)
+
+-- Optimizer step 1. Pushes indexes and concats to the right and separates maps/products/sums.
+step :: A t u -> A t u
+step (Comp (Map (Comp a a2)) a3) = step (Map (step a)) . (Map a2 . a3)
+step (Comp (Map (Prod a a2)) a3) = Zip . ((Map a *** Map a2) . (Unzip . a3))
+step (Comp Index (Prod (Map a) a2)) = step a . (Index . second a2)
+step (Comp Index (Prod Count a)) = arr (\(i, j) -> if inRange (0, i - 1) j then j else error "DataParallel.eval: bad index") . second a
+step (Comp Concat (Map (Map a))) = Map (step a) . Concat
+step (Comp Concat (Map Concat)) = Concat . Concat
+step (Comp (Prod (Comp a a2) a3) a4) = step (Prod (step a) id) . (Prod a2 a3 . a4)
+step (Comp (Prod a (Comp a2 a3)) a4) = step (Prod id (step a2)) . (Prod a a3 . a4)
+step (Comp (Sum (Comp a a2) a3) a4) = step (Sum (step a) id) . (Sum a2 a3 . a4)
+step (Comp (Sum a (Comp a2 a3)) a4) = step (Sum id (step a2)) . (Sum a a3 . a4)
+step (Comp a (Comp a2 a3)) = case step (a . a2) of Comp a4 a5 -> a4 . step (a5 . a3)
+step a = a
+
+-- Optimizer step 2. Replaces nested arrays with the packed representation.
+step2 :: A t u -> A t u
+step2 (Map (Map a)) = Unpack . step2 (Map (step2 a)) . Pack
+step2 (Map a) = case step2 a of
+	Map a -> Unpack . Map a . Pack
+	a -> Map a
+step2 (Prod a a2) = Prod (step2 a) (step2 a2)
+-- Sums create the possibility of recursion trees w/ variable depth.
+step2 (Sum a (Map a2)) = UnpackSum . Map (Sum (step2 a) (step2 a2)) . PackSum
+step2 (Sum (Map a) a2) = arr mirror . step2 (Sum a2 (Map a)) . arr mirror
+step2 (Sum a a2) = Sum (step2 a) (step2 a2)
+step2 (Comp a a2) = step2 a . step2 a2
+step2 a = a
+
+-- Optimizer step 3. Removes redundant packs and zips, combines maps/products/sums, pushes zips right.
+step3 :: A t u -> Maybe (A t u)
+step3 (Comp (Map a) (Comp (Map a2) a3)) = Just $ Map (repetition step3 (a . a2)) . a3
+step3 (Comp Zip (Prod (Map a) (Map a2))) = Just $ Map (repetition step3 (a *** a2)) . Zip
+step3 (Comp Zip (Prod Count Count)) = Just $ Map (arr (\x -> (x, x))) . (Count . arr (uncurry min))
+step3 (Comp Zip (Comp Unzip a)) = Just a
+step3 (Comp Pack (Comp Unpack a)) = Just a
+step3 (Comp PackSum (Comp UnpackSum a)) = Just a
+step3 (Comp (Prod a a2) (Prod a3 a4)) = Just $ repetition step3 (a . a3) *** repetition step3 (a2 . a4)
+step3 (Comp (Sum a a2) (Sum a3 a4)) = Just $ repetition step3 (a . a3) +++ repetition step3 (a2 . a4)
+step3 (Comp a (Comp a2 a3)) = liftM (a .) (step3 (a2 . a3))
+step3 _ = Nothing
+
+repetition f x = maybe x (repetition f) (f x)
+
+-- | Optimizes an arrow for parallel execution. The arrow can be optimized once, and the result saved for multiple computations.
+--   (The exact output of the optimizer is subject to change.)
+optimize a = repetition step3 $ reassociate (step2 $ step $ reassociate a (arr id)) (arr id)
+
+-- | Evaluates arrows.
+eval :: A t u -> t -> u
+eval Count n = inject $ unsafePerformIO $ concF n (return $!)
+eval Index (ArrC ar _, i) = ar ! i
+eval Zip (ArrC ar _, ArrC ar2 _) = inject $ unsafePerformIO $ concF (snd (bounds ar) `min` snd (bounds ar2))
+	(\i -> let x = ar ! i; y = ar2 ! i in x `seq` y `seq` return $! (x, y))
+eval Unzip ar = (fmap fst ar, fmap snd ar)
+eval Concat ar0 = ArrC ar [ Node (i + j) ls3 | Node i ls2 <- ls, Node j ls3 <- ls2 ] where ArrC ar ls = eval Pack ar0
+eval (Map a) (ArrC ar ls) = ArrC (unsafePerformIO $ conc $ fmap ((return $!) . eval a) ar) ls
+eval Pack (ArrC ar ls) = ArrC (newArray $ concatMap (elems . project) $ elems ar)
+	(zipWith Node (scanl (\i (ArrC ar _) -> i + rangeSize (bounds ar)) 0 $ elems ar)
+		(map (\(ArrC _ ls) -> ls) (elems ar) ++ [[]]))
+eval Unpack (ArrC ar ls) = inject $ newArray $ map
+	(\(Node i ls, Node j _) -> ArrC (ixmap (0, j-i-1) (+i) ar) ls)
+	(pairUp ls)
+eval PackSum (Left x) = inject (newArray [Left x])
+eval PackSum (Right ar) = fmap Right ar
+eval UnpackSum ar = either Left (\_ -> Right (fmap (\(Right x) -> x) ar)) (project ar ! 0)
+eval (Comp a a2) x = eval a $ eval a2 x
+eval (Arr f) x = f x
+eval (Prod a a2) (x, y) = b `seq` c `seq` (b, c) where
+	b = eval a x; c = eval a2 y
+eval (Sum a a2) ei = either (Left . eval a) (Right . eval a2) ei
+
diff --git a/Control/Concurrent/Deadlock.hs b/Control/Concurrent/Deadlock.hs
new file mode 100644
--- /dev/null
+++ b/Control/Concurrent/Deadlock.hs
@@ -0,0 +1,154 @@
+{-# LANGUAGE GADTs, ParallelListComp #-}
+
+-- | Automatic deadlock prevention.
+--
+-- Automatic deadlock detection is inefficient, and computations cannot be rolled
+-- back or aborted in general.
+--
+-- Instead, we prevent deadlocks before they happen.
+module Control.Concurrent.Deadlock (Res(Lift, Acq, Rel, Fork, Plus, Id), run, lft) where
+
+import Control.Category
+import Control.Arrow
+import Control.Monad
+import Data.Map (Map)
+import Data.List (inits, tails, elemIndex, deleteBy)
+import Data.Maybe
+import Data.Function (on)
+import qualified Data.Map as M
+import System.IO.Unsafe
+import Control.Concurrent
+import Prelude hiding (id, (.))
+
+-- The typical sequence that produces a deadlock is as follows:
+--
+-- (1) Thread 1 acquires lock A
+-- (2) Thread 2 acquires lock B
+-- (3) Thread 1 tries to acquire B
+-- (4) Thread 2 tries to acquire A
+-- Deadlock.
+--
+-- Standard deadlock detection intervenes after (4) has occurred.
+-- We should intervene in a lock acquisition that is followed
+-- by an unsafe schedule (here at (2)). We suspend thread 2
+-- until a safe schedule is guaranteed -- in this case until
+-- thread 1 relinquishes lock A.
+--
+-- We need to do some kind of static analysis on the threads
+-- to do this. Haskell arrows make possible a kind of JIT
+-- static analysis. We leverage the fact that considerable
+-- computation has been done to reach a certain point --
+-- we only have to analyse the immediate continuation of
+-- a thread.
+
+-- | The Res arrow.
+data Res t u where
+	Lift :: Kleisli IO t v -> Res v u -> Res t u
+	Acq :: MVar () -> Res t u -> Res t u -- acquire a lock
+	Rel :: MVar () -> Res t u -> Res t u -- release a lock
+	Fork :: Res t () -> Res t u -> Res t u -- fork a thread
+	Plus :: Res t v -> Res u v -> Res (Either t u) v -- choice
+	Id :: Res t t
+
+instance Category Res where
+	id = Id
+	a . Lift k a2 = Lift k (a . a2)
+	a . Acq m a2 = Acq m (a . a2)
+	a . Rel m a2 = Rel m (a . a2)
+	a . Fork a2 a3 = Fork a2 (a . a3)
+	a . Plus a2 a3 = Plus (a . a2) (a . a3)
+	a . Id = a
+
+instance Arrow Res where
+	arr f = Lift (arr f) Id
+	first (Lift k a) = Lift (first k) (first a)
+	first (Acq m a) = Acq m (first a)
+	first (Rel m a) = Rel m (first a)
+	first (Fork a a2) = Fork (a . arr fst) (first a2)
+	first Id = Id
+
+instance ArrowChoice Res where
+	left a = Plus (arr Left . a) (arr Right)
+
+-- For each thread, we need to track what resources it currently
+-- holds, and for each resource, the resources it may
+-- potentially acquire while holding that resource.
+
+resource :: MVar (Map ThreadId [(MVar (), [MVar ()])])
+{-# NOINLINE resource #-}
+resource = unsafePerformIO (newMVar M.empty)
+
+-- A hazard is an ACQUIRE-HOLD cycle among threads.
+-- We generate all sequences looking for a cycle.
+
+selects ls = [ (y, xs ++ ys) | xs <- inits ls | y:ys <- tails ls ]
+
+generateSequences ls lock = if null ls then
+		return []
+	else do
+		((t, m), xs) <- selects ls
+		lock' <- maybe [] id $ lookup lock m
+		liftM (lock':) $ generateSequences xs lock'
+
+-- If there is a hazard, returns a /guard/ for the hazard, i.e.
+-- a lock which avoids the hazard.
+hazard mp m = liftM (\(ls, i) -> ls !! (i - 1)) $ msum $ map (\ls -> liftM ((,) ls) (elemIndex m ls)) $ generateSequences (M.assocs mp) m
+
+-- This is the static analysis bit.
+acquired :: Res t u -> MVar () -> [MVar ()]
+acquired (Lift _ a) m = acquired a m
+acquired (Acq m' a) m = m' : acquired a m
+acquired (Rel m' _) m | m' == m = []
+acquired (Rel _ a) m = acquired a m
+acquired (Fork a a2) m = acquired a m ++ acquired a2 m
+acquired (Plus a a2) m = acquired a m ++ acquired a2 m
+acquired Id _ = []
+
+insert x y ((x1, _):xs) | x == x1 = (x, y) : xs
+insert x y (pr:xs) = pr : insert x y xs
+insert x y [] = [(x, y)]
+
+-- | Use this to run computations built in the Res arrow.
+--   Pieces of the arrow that hold locks must be finitely examinable,
+--   otherwise it doesn't terminate.
+run :: Res t u -> t -> IO u
+run (Lift k a) x = runKleisli k x >>= run a
+run (Acq m a) x = do
+	-- Add this lock to held locks.
+	mp <- takeMVar resource
+	thd <- myThreadId
+	let mp' = M.alter (Just . insert m (acquired a m) . maybe [] id) thd mp
+
+	-- Have to see if acquiring this lock creates a hazard
+	-- involving possibly acquired locks.
+	let may = hazard mp' m
+	maybe
+		(do
+			putMVar resource mp'
+			takeMVar m
+			run a x)
+		-- Waits on the lock. This has the effect of denying service
+		-- to this thread until the hazard has passed.
+		(\m' -> do
+			putMVar resource mp
+			run (Acq m' $ Rel m' $ Acq m a) x)
+		may
+run (Rel m a) x = do
+	putMVar m ()
+	thd <- myThreadId
+	modifyMVar_ resource (return . M.adjust (deleteBy ((==) `on` fst) (m, [])) thd)
+	run a x
+run (Fork a a2) x = forkIO (run a x) >> run a2 x
+run (Plus a a2) ei = either (run a) (run a2) ei
+run Id x = return x
+
+lft m = Lift $ Kleisli $ \x -> m >> return x
+
+-- This implements the example above, using the primitives of this library.
+test = do
+	m1 <- newMVar ()
+	m2 <- newMVar ()
+	run (Fork (lft (print "Thd1 done") Id . Rel m1 Id . Rel m2 Id . Acq m1 Id . lft (threadDelay 1000000) Id . Acq m2 Id)
+		(lft (print "Thd2 done") Id . Rel m1 Id . Rel m2 Id . Acq m2 Id . lft (threadDelay 1000000) Id . Acq m1 Id))
+		()
+
diff --git a/Control/Concurrent/FChan.hs b/Control/Concurrent/FChan.hs
new file mode 100644
--- /dev/null
+++ b/Control/Concurrent/FChan.hs
@@ -0,0 +1,45 @@
+{-# LANGUAGE DeriveDataTypeable #-}
+
+-- | Functional channels
+-- | A channel data type which allows consumers to hold references to different points in a stream at the same time. Elements of a channel are kept alive only so long as there are references pointing before those elements. And producers on a channel are kept alive only so long as there are consumers.
+module Control.Concurrent.FChan (Chan, DoneReadingException(..), takeChan, newChan, makeConsumer) where
+
+import Control.Concurrent.MVar
+import Control.Exception
+import System.Mem.Weak
+import Data.Typeable
+
+newtype Chan t = Chan (MVar (t, Chan t))
+
+-- | Thrown by the writer function when the garbage collector detects that no one will read it.
+data DoneReadingException = DoneReadingException deriving (Typeable, Show)
+
+instance Exception DoneReadingException
+
+addChan vr x = modifyMVar_ vr (\weak -> do
+	may <- deRefWeak weak
+	case may of
+		Just vr2 -> do
+			vr' <- newEmptyMVar
+			putMVar vr2 (x, Chan vr')
+			mkWeak vr' vr' Nothing
+		Nothing -> throwIO DoneReadingException)
+
+-- | Take the first element from a channel, and a channel representing the remainder of the output.
+takeChan (Chan vr) = readMVar vr
+
+-- | Create a new channel. The first return value is a function that can be used to add values to the channel. The second return value is the channel itself.
+newChan = do
+	vr <- newEmptyMVar
+	weak <- mkWeak vr vr Nothing
+	vr2 <- newMVar weak
+	return (addChan vr2, Chan vr)
+
+-- | The first return value is a thunk that returns values from the channel successively, starting from the position of the parameter channel. The second thunk can be used to retrieve the position of the channel after all the reads made using the first thunk.
+makeConsumer chn = do
+	vr2 <- newMVar chn
+	return (modifyMVar vr2 (\chn -> do
+		(x, chn2) <- takeChan chn
+		return (chn2, x)),
+		readMVar vr2)
+
diff --git a/Control/Concurrent/Processes.hs b/Control/Concurrent/Processes.hs
new file mode 100644
--- /dev/null
+++ b/Control/Concurrent/Processes.hs
@@ -0,0 +1,68 @@
+-- | An implementation of communicating sequential processes.
+module Control.Concurrent.Processes (CSP(..), runCSP0, runCSP) where
+
+import Control.Concurrent (forkIO)
+import Control.Concurrent.MVar
+import Control.Concurrent.FChan
+import Data.List
+import Control.Monad
+import qualified Control.Exception as E
+
+infixr 1 :->
+
+-- | The CSP data type:
+--   :||  - interleave
+--   :?   - deterministic choice
+--   Join - interface parallel
+--   :->  - prefix
+--   Stop - empty computation
+--   Do   - execute IO, then behave as the returned process
+data CSP = CSP :|| CSP | CSP :? CSP | Join CSP [String] CSP | String :-> CSP | Stop | Do (IO CSP) deriving Show
+
+instance Show (IO t) where
+	showsPrec _ _ = ("<IO action>"++)
+
+data Side = N | L | R deriving Eq
+
+prefix emitToken chan halt s p = do
+	let may = find (\(int, (_, s2, _):tl) -> s2 == s) (init (zip (inits halt) (tails halt)))
+	case may of
+		Just (int, (status, _, side):tl) -> do
+			side2 <- takeMVar status
+			if side2 == N || side == side2 then do
+					-- Waiting
+					putMVar status side
+					runCSP0 chan (int ++ tl) ((s :-> p) :? ("" :-> Stop))
+				else do
+					-- Wake up
+					putMVar status side2
+					when emitToken (E.catch (fst chan s) (\DoneReadingException -> return ()))
+					runCSP0 chan (int ++ tl) p
+		Nothing -> do
+			when emitToken (E.catch (fst chan s) (\DoneReadingException -> return ()))
+			runCSP0 chan halt p
+
+runCSP0 chan halt (p1 :|| p2) = do
+	forkIO (runCSP0 chan halt p1)
+	runCSP0 chan halt p2
+runCSP0 chan halt ((s1 :-> p1) :? (s2 :-> p2)) = do
+	consumer <- makeConsumer (snd chan)
+	let taking = fst consumer >>= \s -> if s `elem` [s1, s2] then return s else taking
+	s <- taking
+	newChan <- snd consumer
+	prefix False (fst chan, newChan) halt s (if s == s1 then p1 else p2)
+runCSP0 chan halt (Join p1 ls p2) = do
+	statuses <- mapM (const (newMVar N)) ls
+	forkIO (runCSP0 chan (zip3 statuses ls (repeat L) ++ halt) p1)
+	runCSP0 chan (zip3 statuses ls (repeat R) ++ halt) p2
+runCSP0 chan halt (s :-> p) = prefix True chan halt s p
+runCSP0 chan halt Stop = return ()
+runCSP0 chan halt (Do io) = do
+	p <- io
+	runCSP0 chan halt p
+
+-- | Run a CSP computation.
+runCSP p = do
+	chan <- newChan
+	runCSP0 chan [] p
+
diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,339 @@
+             GNU GENERAL PUBLIC LICENSE
+                Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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+
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+
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diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain