module Bit where

import Test.QuickCheck


data Bit = None | Zero | One
         deriving (Eq)

instance Show Bit where
    show None = "None"
    show Zero = "0"
    show One  = "1"


instance Arbitrary Bit where
    arbitrary = elements [ Zero, One ]
    coarbitrary _ = variant 0


bit_to_int :: Bit -> Int
bit_to_int None = -1
bit_to_int Zero =  0
bit_to_int One  =  1

-- If we are passed a '0' or '1', convert it appropriately. Otherwise,
-- default to None.
bit_from_char :: Char -> Bit
bit_from_char '0' = Zero
bit_from_char '1' = One
bit_from_char  _  = None