Cool! I actually starred your project last year. Never really got around to looking under the hood though. How do you handle the "multiple destinations" part? In python you can do it with a coroutines [1, 2] implementation (push based). I avoided that, since it coroutines have their own form of callback hell, and decided to implement a generator api (pull based) [3, 4].

But since generators can only be "pulled" into one destination, you have to copy a stream (subsequently converting it into a list) if you want more than one destination [5]. This works fine if the data can fit in memory, but if it can't then you're out of luck!

[1] http://www.dabeaz.com/coroutines/copipe.py

[2] http://www.dabeaz.com/coroutines/

[3] http://www.dabeaz.com/generators/retuple.py

[4] http://www.dabeaz.com/generators

[5] https://github.com/nerevu/riko/blob/master/riko/modules/spli...