diff --git a/AFSM.cabal b/AFSM.cabal
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+++ b/AFSM.cabal
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+-- Initial AFSM.cabal generated by cabal init.  For further documentation, 
+-- see http://haskell.org/cabal/users-guide/
+
+-- The name of the package.
+name:                AFSM
+
+-- The package version.  See the Haskell package versioning policy (PVP) 
+-- for standards guiding when and how versions should be incremented.
+-- http://www.haskell.org/haskellwiki/Package_versioning_policy
+-- PVP summary:      +-+------- breaking API changes
+--                   | | +----- non-breaking API additions
+--                   | | | +--- code changes with no API change
+version:             0.1.0.0
+
+-- A short (one-line) description of the package.
+synopsis:            Arrowized functional state machines
+
+-- A longer description of the package.
+description: Arrowized functional state machines.
+             This module is inspired by Yampa and the paper 
+             /Functional Reactive Programming, Continued*/ written by
+             Henrik Nilsson, Antony Courtney and John Peterson.        
+
+-- URL for the project homepage or repository.
+homepage:            https://github.com/FiveEye/AFSM
+
+-- The license under which the package is released.
+license:             MIT
+
+-- The file containing the license text.
+license-file:        LICENSE
+
+-- The package author(s).
+author:              Hanzhong Xu
+
+-- An email address to which users can send suggestions, bug reports, and 
+-- patches.
+maintainer:          hanzh.xu@gmail.com
+
+-- A copyright notice.
+-- copyright:           
+
+category:            FRP
+
+build-type:          Simple
+
+-- Extra files to be distributed with the package, such as examples or a 
+-- README.
+-- extra-source-files:  
+--   examples/RPN.hs
+-- Constraint on the version of Cabal needed to build this package.
+cabal-version:       >=1.10
+
+
+library
+  -- Modules exported by the library.
+  exposed-modules:     Control.AFSM
+  
+  -- Modules included in this library but not exported.
+  -- other-modules:       
+  
+  -- LANGUAGE extensions used by modules in this package.
+  other-extensions:    Arrows, GADTs
+  
+  -- Other library packages from which modules are imported.
+  build-depends:       base >=4.7 && <4.8
+  
+  -- Directories containing source files.
+  hs-source-dirs:      src
+  
+  -- Base language which the package is written in.
+  default-language:    Haskell2010
+  
+source-repository head
+  type: git
+  location: git@github.com:FiveEye/AFSM.git
diff --git a/LICENSE b/LICENSE
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+++ b/LICENSE
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+Copyright (c) 2016 Hanzhong Xu
+
+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/Setup.hs b/Setup.hs
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+++ b/Setup.hs
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+import Distribution.Simple
+main = defaultMain
diff --git a/src/Control/AFSM.hs b/src/Control/AFSM.hs
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+++ b/src/Control/AFSM.hs
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+{-# LANGUAGE GADTs #-}
+
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  
+-- Copyright   :  (c) Hanzhong Xu 2016,
+-- License     :  MIT License
+--
+-- Maintainer  :  hanzh.xu@gmail.com
+-- Stability   :  experimental
+-- Portability :  portable
+--
+-- Arrowized functional state machines.
+--
+--   This module is inspired by Yampa and the paper 
+--   /Functional Reactive Programming, Continued*/ written by
+--     Henrik Nilsson, Antony Courtney and John Peterson.
+-----------------------------------------------------------------------------
+
+module Control.AFSM (
+  module Control.Arrow,
+  
+  -- * The 'SM' type
+  SM,
+  
+  -- * The 'SMState' type
+  SMState,
+  
+  -- * Constructors
+  newSM,
+  simpleSM,
+  
+  -- * High order functions
+  execSM,
+  
+  -- * Evaluation
+  exec
+  
+) where
+
+import Control.Category
+import Control.Arrow
+
+type SMState r a b = (r -> a -> (SM a b, b))
+
+-- | 'SM' is a type representing a state machine.
+data SM a b where 
+  SM :: r -> (SMState r a b) -> SM a b
+  
+-- Constructors
+
+newSM :: r -> (SMState r a b) -> SM a b
+newSM = SM
+
+simpleSM :: r -> (r -> a -> (r, b)) -> SM a b
+simpleSM r f = SM r f'
+  where
+    f' = (\r' a' -> let (r'', b) = f r' a' in (SM r'' f', b))
+
+-- Category instance    
+
+instance Category SM where
+  id  = idSM
+  (.) = composeSM
+  
+idSM :: SM a a
+idSM = SM () (\_ a -> (idSM, a))
+  
+composeSM :: SM b c -> SM a b -> SM a c
+composeSM sm1 sm0 = SM (sm0,sm1) f2
+  where
+    f2 ((SM r0 f0),(SM r1 f1)) a = (SM (sm0', sm1') f2, c)
+      where
+        (sm0', b) = f0 r0 a
+        (sm1', c) = f1 r1 b
+
+        
+-- Arrow instance
+  
+instance Arrow SM where
+  arr = arrSM
+  first = firstSM
+  second = secondSM
+  (***) = productSM
+  (&&&) = fanoutSM
+
+arrSM :: (a -> b) -> SM a b
+arrSM f =
+  SM () (\_ a ->(arrSM f, f a))
+          
+firstSM :: SM a b -> SM (a, c) (b, c)
+firstSM sm = SM sm f1
+  where
+    f1 (SM r f) (a,c) = ((SM sm' f1), (b, c))
+      where
+        (sm', b) = f r a
+        
+secondSM :: SM a b -> SM (c, a) (c, b)
+secondSM sm = SM sm f1
+  where
+    f1 (SM r f) (c,a) = ((SM sm' f1), (c, b))
+      where
+        (sm', b) = f r a
+
+productSM :: SM a b -> SM c d -> SM (a, c) (b, d)
+productSM sm0 sm1 = SM (sm0, sm1) f2
+  where
+    f2 ((SM r0 f0),(SM r1 f1)) (a, c) = (SM (sm0', sm1') f2, (b, d))
+      where
+        (sm0', b) = f0 r0 a
+        (sm1', d) = f1 r1 c
+
+fanoutSM :: SM a b -> SM a c -> SM a (b, c)
+fanoutSM sm0 sm1 = SM (sm0, sm1) f2
+  where
+    f2 ((SM r0 f0),(SM r1 f1)) a = (SM (sm0', sm1') f2, (b, c))
+      where
+        (sm0', b) = f0 r0 a
+        (sm1', c) = f1 r1 a
+
+-- Evaluation
+
+exec :: SM a b -> [a] -> (SM a b, [b])
+exec sm [] = (sm, [])
+exec (SM r f) (x:xs) = (sm'', b:bs)
+  where 
+    (sm', b) = f r x
+    (sm'', bs) = (exec sm' xs)
+    
+-- High order functions
+    
+execSM :: SM a b -> SM [a] [b]
+execSM sm = simpleSM sm exec