src/Bit.hs

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