Python truth table calculator

truthtable.py

#!/usr/bin/python2
# based on: https://gist.github.com/pindia/3836713
from itertools import izip, product, tee

# Logic functions: take and return iterators of truth values

def AND(a, b):
    for p, q in izip(a, b):
        yield p and q

def OR(a, b):
    for p, q in izip(a, b):
        yield p or q
        
def XOR(a, b):
    for p, q in izip(a, b):
        yield not(p is q)

def NOT(a):
    for p in a:
        yield not p

def EQUIV(a, b):
    for p, q in izip(a, b):
        yield p is q

def IMPLIES(a, b):
    for p, q in izip(a, b):
        yield (not p) or q

def create(num=2):
    ''' Returns a list of all of the possible combinations of truth for the given number of variables.
    ex. [(T, T), (T, F), (F, T), (F, F)] for two variables '''
    return list(product([True, False], repeat=num))

def unpack(data):
    ''' Regroups the list returned by create() by variable, making it suitable for use in the logic functions.
    ex. [(T, T, F, F), (T, F, T, F)] for two variables '''
    return [[elem[i] for elem in lst] for i, lst in enumerate(tee(data, len(data[0])))]

def print_result(data, result):
    ''' Prints the combinations returned by create() and the results returned by the logic functions in a nice format. '''
    n = len(data[0])
    headers = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'[:n]
    print headers + "|RESULT"
    print '-' * len(headers) + '+------'
    for row, result_cell in izip(data, result):
        print ''.join({True: '1', False:'0'}[cell] for cell in row) + '|' + '  ' + {True: '1', False:'0'}[result_cell]

if __name__ == '__main__':
    data = create(num=4)
    A, B, C, D = unpack(data)
    #  ((a XOR b) OR (c AND d)) AND (a AND b) OR (NOT c)
    result = OR(AND(OR(XOR(A,B),AND(C,D)),AND(A,B)),NOT(C))
    print_result(data, result)