-- | The Bit module contains the Bit data type, which is essentially a
--   renamed Boolean, and some convenience functions.
module Bit
where

import Test.QuickCheck (
  Arbitrary,
  arbitrary,
  elements
  )


data Bit = Zero | One
  deriving (Eq)

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


instance Arbitrary Bit where
  arbitrary = elements [ Zero, One ]


-- | Convert a Bit to an Int.
bit_to_int :: Bit -> Int
bit_to_int Zero =  0
bit_to_int One  =  1

-- | If we are passed a '0' or '1', convert it
--   appropriately. Otherwise, return Nothing.
bit_from_char :: Char -> Maybe Bit
bit_from_char '0' = Just Zero
bit_from_char '1' = Just One
bit_from_char  _  = Nothing