src/Bit.hs

   1 -- | The Bit module contains the Bit data type, which is essentially a
   2 --   renamed Boolean, and some convenience functions.
   3 module Bit
   4 where
   5
   6 import Test.QuickCheck (
   7   Arbitrary,
   8   arbitrary,
   9   elements
  10   )
  11
  12
  13 data Bit = Zero | One
  14   deriving (Eq)
  15
  16 instance Show Bit where
  17   show Zero = "0"
  18   show One  = "1"
  19
  20
  21 instance Arbitrary Bit where
  22   arbitrary = elements [ Zero, One ]
  23
  24
  25 -- | Convert a Bit to an Int.
  26 bit_to_int :: Bit -> Int
  27 bit_to_int Zero =  0
  28 bit_to_int One  =  1
  29
  30 -- | If we are passed a '0' or '1', convert it
  31 --   appropriately. Otherwise, return Nothing.
  32 bit_from_char :: Char -> Maybe Bit
  33 bit_from_char '0' = Just Zero
  34 bit_from_char '1' = Just One
  35 bit_from_char  _  = Nothing