generator vs. coroutines vs. async/await

async-await.py

import asyncio

async def compute(x, y):
    print("Compute %s + %s ..." % (x, y))
    await asyncio.sleep(1.0)
    return x + y

async def print_sum(x, y):
    result = await compute(x, y)
    print("%s + %s = %s" % (x, y, result))

loop = asyncio.get_event_loop()
loop.run_until_complete(print_sum(1, 2))
loop.close()

coroutines.py

import asyncio


@asyncio.coroutine
def compute(x, y):
    print("Compute %s + %s ..." % (x, y))
    yield from asyncio.sleep(1.0)
    return x + y


@asyncio.coroutine
def print_sum(x, y):
    result = yield from compute(x, y)
    print("%s + %s = %s" % (x, y, result))


loop = asyncio.get_event_loop()
loop.run_until_complete(print_sum(1, 2))
loop.close()

generator-from.py

def compute(x, y):
    print("Compute %s + %s ..." % (x, y))
    yield 1  # assume sleep 1 second
    return x + y


def print_sum(x, y):
    result = yield from compute(x, y)
    print("%s + %s = %s" % (x, y, result))


try:
    gens = print_sum(1, 2)
    while True:  # emulate event loop
        next(gens)
except StopIteration:
    print("Done")

generator.py

def compute(x, y):
    print("Compute %s + %s ..." % (x, y))
    yield 1  # sleep 1 second
    return x + y


def print_sum(x, y):
    try:
        gens = compute(x, y)
        while True:
            yield next(gens)
    except StopIteration as e:
        result = e.value
        print("%s + %s = %s" % (x, y, result))


def main():
    try:
        gens = print_sum(1, 2)
        while True:
            next(gens)
    except StopIteration:
        print("Done")

Reference:

• https://docs.python.org/3/library/asyncio-task.html
• http://masnun.com/2015/11/13/python-generators-coroutines-native-coroutines-and-async-await.html