From 5825a18ea1267c1f769a054c650b2761de7f291c Mon Sep 17 00:00:00 2001
From: Michael Orlitzky <michael@orlitzky.com>
Date: Sun, 2 May 2010 15:18:25 -0400
Subject: [PATCH] Add a None constructor for Bits.

---
 src/Bit.hs | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/Bit.hs b/src/Bit.hs
index 1c7de7b..7c18408 100644
--- a/src/Bit.hs
+++ b/src/Bit.hs
@@ -1,15 +1,16 @@
 module Bit where
 
-data Bit = Zero | One
+data Bit = None | Zero | One
          deriving (Eq, Show)
 
 bit_to_int :: Bit -> Int
-bit_to_int Zero = 0
-bit_to_int One  = 1
+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 Zero.
+-- default to None.
 bit_from_char :: Char -> Bit
 bit_from_char '0' = Zero
 bit_from_char '1' = One
-bit_from_char  _  = Zero
+bit_from_char  _  = None
-- 
2.43.2