Oh my me. This is a very long thread that I probably should have replied to a long time ago. This thread is intensely long right now, and tonight is the first chance I've had to try and go through it comprehensively. I'll try to reply to individual points made in the thread -- if I missed yours, please don't be offended, I promise it's my fault :) FYI, I'm the sucker who originally got tricked into starting PEP 3153, aka async-pep. First of all, I'm glad to see that there's some more "let's get that pep along" movement. I tabled it because: a) I didn't have enough time to contribute, b) a lot of promised contributions ended up not happening when it came down to it, which was incredibly demotivating. The combination of this thread, plus the fact that I was strong armed at Pycon ZA by a bunch of community members that shall not be named (Alex, Armin, Maciej, Larry ;-)) into exploring this thing again. First of all, I don't feel async-pep is an attempt at twisted light in the stdlib. Other than separation of transport and protocol, there's not really much there that even smells of twisted (especially since right now I'd probably throw consumers/producers out) -- and that separation is simply good practice. Twisted does the same thing, but it didn't invent it. Furthermore, the advantages seem clear: reusability and testability are more than enough for me. If there's one take away idea from async-pep, it's reusable protocols. The PEP should probably be a number of PEPs. At first sight, it seems that this number is at least four: 1. Protocol and transport abstractions, making no mention of asynchronous IO (this is what I want 3153 to be, because it's small, manageable, and virtually everyone appears to agree it's a fantastic idea) 2. A base reactor interface 3. A way of structuring callbacks: probably deferreds with a built-in inlineCallbacks for people who want to write synchronous-looking code with explicit yields for asynchronous procedures 4+ adapting the stdlib tools to using these new things Re: forward path for existing asyncore code. I don't remember this being raised as an issue. If anything, it was mentioned in passing, and I think the answer to it was something to the tune of "asyncore's API is broken, fixing it is more important than backwards compat". Essentially I agree with Guido that the important part is an upgrade path to a good third-party library, which is the part about asyncore that REALLY sucks right now. Regardless, an API upgrade is probably a good idea. I'm not sure if it should go in the first PEP: given the separation I've outlined above (which may be too spread out...), there's no obvious place to put it besides it being a new PEP. Re base reactor interface: drawing maximally from the lessons learned in twisted, I think IReactorCore (start, stop, etc), IReactorTime (call later, etc), asynchronous-looking name lookup, fd handling are the important parts. call_every can be implemented in terms of call_later on a separate object, so I think it should be (eg twisted.internet.task.LoopingCall). One thing that is apparently forgotten about is event loop integration. The prime way of having two event loops cooperate is *NOT* "run both in parallel", it's "have one call the other". Even though not all loops support this, I think it's important to get this as part of the interface (raise an exception for all I care if it doesn't work). cheers lvh