Re: Await expressions

ram@zedat.fu-berlin.de (Stefan Ram) writes:

(Then, it should also be interesting to understand how asyncio
uses "await" to implement asynchronous I/O.)

  I have taken "sleep" from asyncio\tasks.py and simplified it a bit:

async def sleep( delay, result=None, *, loop=None ):

    loop = events.get_running_loop()

    future = loop.create_future()

    h = loop.call_later
    ( delay, futures._set_result_unless_cancelled, future, result )
   
    try: return await future
    finally: h.cancel()

  So, this is how the control is transferred to the event
  loop after an "await sleep"! Initially, the control goes
  to "sleep", but this transfers the control to the event loop
  (until "sleep" stops waiting for its future in "await future").