Haskell machine package examples

examples.hs

module Examples where

import Control.Applicative
import Control.Monad.Trans

import Data.Machine

data Bit = EMPTY | One | Zero

instance Show Bit where
  show One  = "1"
  show Zero = "0"
  show _    = ""

-- Binary adding machine
adding :: Moore Bit Bit
adding = Moore EMPTY carried
  where
    absorbed One  = Moore One absorbed
    absorbed Zero = Moore Zero absorbed
    carried  One  = Moore Zero carried
    carried  Zero = Moore One absorbed

printer :: (MonadIO m, Show a) => ProcessT m a ()
printer = repeatedly $ liftIO . print =<< await

little_endian = reverse

test = printer <~ auto adding <~ source (little_endian [Zero, One, Zero, One]) -- prints [0,1,1,0]