\begin{code}

{-|
Description: Finite state transducers with epsilon-transitions
-}
module Control.FST
  ( FST(..)
  ) where

import Data.Map.Strict (Map)
import qualified Data.Map.Strict as Map

import Data.Set (Set)

import Data.Sequence (Seq)

import Control.Lens.TH

data FST state input output = FST
  { stInitial :: state
  , stTransition :: Map (state, Maybe input) (Set (state, Maybe output))
  , stAccept :: Set state
  }
\end{code}