Coroutine pipeline

coroutine_pipeline.py

"""
Coroutine pipeline.

Based off https://www.lua.org/pil/9.2.html.
"""

import types

if __name__ == '__main__':

    def receive(prod):
        return prod.send(None)

    @types.coroutine
    def send(x):
        yield x

    async def producer():
        while True:
            x = input("? ")
            await send(x)

    def filter(prod):
        async def _filter():
            line = 1
            while True:
                x = receive(prod)
                await send("%5d %s" % (line, x))
                line = line + 1

        return _filter()

    def consumer(prod):
        while True:
            x = receive(prod)
            print(x)

    # Simple pipeline
    consumer(filter(producer()))