There are other concepts, like coroutines. At work, I use Lua coroutines to handle network requests. Basically, any function that can block instead starts the

There are other concepts, like coroutines. At work, I use Lua coroutines to handle network requests. Basically, any function that can block instead starts the IO request, then yields the current coroutine. Yeah, the management code was a bit of a pain to write, but you can write (using the BASIC example from the article and not Lua, but the idea is similar): 10 A = 1 20 A = A + 1 30 PRINT "HELLO " + A 40 PRINT "YES" 50 GOTO 20 where `PRINT` will do a non-blocking write, if there's anything left over, set the IO descriptor to trigger when ready for writing, and yield(). It's in the poll loop (select(), poll(), epoll(), kevent(), whatever the API is) to schedule the proper coroutine. Yes, this requires making sure the code doesn't do anything CPU intensive, but for the application I have running, that is the case. But for me, using Lua coroutines means the main business logic is still sequential, even in an event driving environment. Also, because you call a function to preempt execution, you don't need to save the entire CPU state. For C on the x86-64 bit, this is just six registers: https://github.com/spc476/C-Coroutines/blob/314607cf058352bee922a4c0d1cfc0a37646d250/coroutine_yield-x86-64.asm#L85 https://github.com/spc476/C-Coroutines/blob/314607cf058352be...