continuation.py

from collections import namedtuple
import decorator

@decorator.decorator
def continuate(gen, *args, **kwargs):

    it = gen(*args, **kwargs)

    def continuation():
        try:
            next(it)(continuation)
        except StopIteration:
            pass

    continuation()

@continuate
def foo():
    print('a')
    print((yield lambda(c): bar(c, 4)))
    print('b')

KeySubscriber = namedtuple('KeySubscriber', ['callback', 'keys'])

subscribers = set()


def listen_for_key_event_async(subscriber):
    subscribers.append(subscriber)


def handle_key(key):
    for s in set(subscribers):
        if key in s.keys:
            s.callback(key)
            subscribers.remove(s)