Except one thing, as you pointed out, people use Node.js -- 1) it is JS 2) V8 is fast.
Twisted's inlinecallback's and tornado's gen module gets rid of all the async spaghetti code. This is hard to do with nodejs but I still chose nodejs because the available libraries made my project quicker to develop.
Basically yes, Python had Twisted for years, it had Diesel, Monocle, Tornado, and some other ones. I am aware of those and as you've read my comment you saw that I used Twisted enough to know its ins and outs (5 years).
> There are also async frameworks that make writing async code the same as synchronous code.
Yes there is inlineCallbacks and I used. Node.js also has async (https://github.com/caolan/async). But you don't address the main problem that I raised -- fragmentation of libraries. Python is great because it comes with batteries, and then you can find even more batteries everywhere, _except_ if you use an async framework like Twisted, which, percolates all the way through you API code. Once your socket.recv() returns a Deferred(), that deferred will bubble up all the way to the user interface. So you now you end up searching or recreating a parallel set of libraries.
> Twisted has a lot of libraries but it has so much going on that many developers find it too complex.
It is too complex with too many libraries for those who want to take it up but it is not complex and doesn't have enough libraries if you are in it already -- every library you use has to be Twisted now. That's the danger of inventing a new framework.
Yes it will be standard, but there is already a practical standard -- eventlet and gevent. This is somethin Node.js doesn't have. I will personally take monkey-patching and the danger that my function will context switch inside while doing IO over using Twisted. I saw a practical benefit from it at least.
http://taskjs.org/
https://code.google.com/p/v8/issues/detail?id=2355Before it used to be code like:
def processShoppingCart(...):
d.addCallback(_cb1)
return d # (d is a Deferred)
def _cb1(...):
d2.addCallback(_cb2)
return d2 # d2 is a another Deferred
Which with generators and inlineCallbacks turns into
@someDecoratorThatEnableUsingInlineCallbacks
def processShoppingCart(...):
.. do some work ..
yield <some_io_function_like_check_db>
.. do some more work ..
yield <some_io_other_io_function>
....
I have been using Twisted for 5 years full time and have also used eventlet and gevent. From talking to others, I have found few who enjoyed or loved Twisted. It was pretty much the only sane way to do concurrent, performant IO for a while. But then when green thread approach came about, I had never looked back.
All was well. Then one day Node.js showed up, and it seems it has started to eat Python's lunch -- fast, scripted development on the server side, with some reasonable concurrency. And it was faster too.
Python devs looked at it and couldn't believe their eyes. And I speculate many have concluded it was because everyone was in love with a callback based async IO paradigm. So that's my guess why we are seeing this proposal.