Created
June 22, 2017 15:10
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naive async flow like node, using promise
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| import signal | |
| # broken in eventloop things | |
| class Promise: | |
| def __init__(self, f): | |
| self.status = 'PENDING' | |
| self.cb = None | |
| f(self.__resolve) | |
| def resolve(v): | |
| if isinstance(v, Promise): | |
| return v | |
| else: | |
| return Promise(lambda res:res(v)) | |
| def __resolve(self, v): | |
| self.status = 'RESOLVED' | |
| if self.cb: | |
| Promise.resolve(self.cb(v)) | |
| else: | |
| self.value = v | |
| def then(self, cb): | |
| if self.status == 'PENDING': | |
| self.cb = cb | |
| else: | |
| return Promise.resolve(cb(self.value)) | |
| def run(gen, v=None): | |
| try: | |
| ret = gen.send(v) | |
| ret.then(lambda res: run(gen, res)) | |
| except StopIteration as e: | |
| print('gen done') | |
| def sleep(n): | |
| def f(resolve): | |
| signal.signal(signal.SIGALRM, lambda signum, frame: resolve('wake up')) | |
| signal.setitimer(signal.ITIMER_REAL, n) | |
| return Promise(f) | |
| def fakeAjax(): | |
| ret = yield sleep(1) | |
| print(f'after sleep1: {ret}') | |
| ret2 = yield sleep(1) | |
| print(f'after sleep2: {ret2}') | |
| if name == '__main__': | |
| run(fakeAjax()) | |
| print('first one') | |
| # first one | |
| # after sleep1: wake up | |
| # after sleep2: wake up | |
| # gen done |
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