From: Michael Orlitzky <michael@orlitzky.com>
Date: Sun, 2 May 2010 19:18:25 +0000 (-0400)
Subject: Add a None constructor for Bits.
X-Git-Tag: 0.0.1~82
X-Git-Url: http://gitweb.michael.orlitzky.com/?p=hath.git;a=commitdiff_plain;h=5825a18ea1267c1f769a054c650b2761de7f291c

Add a None constructor for Bits.
---

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