dfa2.py

def make_state(name, states, transitions, is_final):

    def state(string, index):
        if index >= len(string):
            return is_final
        cur_input = string[index]
        next_state = transitions[cur_input]
        return states[next_state](string, index + 1)

    states[name] = state

def main2():
    states = {}
    make_state("q0", states, {"0": "q0", "1": "q1"}, True)
    make_state("q1", states, {"0": "q2", "1": "qc"}, False)
    make_state("q2", states, {"0": "q1", "1": "q2"}, False)
    make_state("qc", states, {"0": "q0", "1": "q1"}, False)
    initial = "q0"
    string = raw_input("Enter a string to test >>> ")
    try:
        result = states[initial](string, 0)
    except:
        print "Bad input"
    else:
        print "Accepted!" if result else "Rejected =("

main2()