I don't think the comparison with UI is so apt. Sure, they both use callbacks, but the granularity is quite different. In UI callbacks, you don't need to insert your own "scheduling points" as you need in explicity asynchronous programming. Mostly, you write functions that reacts to the events generated by the UI, but within those event handler, your own code is mostly synchronous.
I wonder why you mean by using callbacks properly ? The critical point mentioned by Guido is error/corner-case handling: the idiomatic callback-based code I have seen becomes difficult very quickly. I have not seen a case where e.g. deferred-based code ala twisted has been simpler than gevent.
I wonder why you mean by using callbacks properly ? The critical point mentioned by Guido is error/corner-case handling: the idiomatic callback-based code I have seen becomes difficult very quickly. I have not seen a case where e.g. deferred-based code ala twisted has been simpler than gevent.