src/Bit.hs

   1 module Bit where
   2
   3 import Test.QuickCheck
   4
   5
   6 data Bit = None | Zero | One
   7          deriving (Eq)
   8
   9 instance Show Bit where
  10     show None = "None"
  11     show Zero = "0"
  12     show One  = "1"
  13
  14
  15 instance Arbitrary Bit where
  16     arbitrary = elements [ Zero, One ]
  17
  18
  19 bit_to_int :: Bit -> Int
  20 bit_to_int None = -1
  21 bit_to_int Zero =  0
  22 bit_to_int One  =  1
  23
  24 -- If we are passed a '0' or '1', convert it appropriately. Otherwise,
  25 -- default to None.
  26 bit_from_char :: Char -> Bit
  27 bit_from_char '0' = Zero
  28 bit_from_char '1' = One
  29 bit_from_char  _  = None