Cleanly separated elementary "guess password" game. Shows extreme separation of concerns and an enhanced generator (coroutines) based solution. The whole structure is as stateless as possible, even when objects are used. Easy stuff made hard. ;)

password_guess.py

import sys

class TextualUI(object):
    def __init__(self, out=sys.stdout):
        self.out = out

    def inform_defeat(self, _max_attempts):
        message = 'You lost.\n'
        self.out.write(message)

    def inform_success(self, attempt, guess, max_attempts):
        message = ('You won with %d/%d attempts. The secret was %s.\n' %
                    (attempt, max_attempts, guess))
        self.out.write(message)

    def inform_failure(self, attempt, guess, max_attempts):
        message = ('Your guess %s is wrong. You used %d/%d attempts.\n' %
                   (guess, attempt, max_attempts))
        self.out.write(message)

    def prompt(self, attempt, max_attempts):
        return '%d/%d> ' % (attempt, max_attempts)

    def initial_prompt(self, max_attempts):
        return self.prompt(1, max_attempts)


def input_generator(initial_prompt='> '):
    prompt = initial_prompt
    while 1:
        prompt = yield raw_input(prompt)
        if prompt is None:
            prompt = initial_prompt

def guess_password(ui, input_stream, secret, max_attempts):
    for attempt, guess in enumerate(input_stream, start=1):
        if secret == guess:
            ui.inform_success(attempt, secret, max_attempts)
            return attempt
        elif attempt == max_attempts:
            ui.inform_defeat(max_attempts)
            return attempt
        else:
            ui.inform_failure(attempt, guess, max_attempts)

def guess_password_prompt(ui, input_stream, secret, max_attempts):
    guess = input_stream.next()
    attempt = 1
    while 1:
        if secret == guess:
            ui.inform_success(attempt, secret, max_attempts)
            return attempt
        elif attempt == max_attempts:
            ui.inform_defeat(max_attempts)
            return attempt
        else:
            ui.inform_failure(attempt, guess, max_attempts)
            attempt += 1
            guess = input_stream.send(ui.prompt(attempt, max_attempts))

if __name__ == "__main__":
    max_attempts = 3
    ui = TextualUI()
    generator = input_generator(ui.initial_prompt(max_attempts))
    secret = 'foo'

    guess_password_prompt(ui, generator, secret, max_attempts)