[Python-ideas] [Python-Dev] Python needs a standard asynchronous return object

[Andrew Bennetts]

Guido van Rossum wrote:
[...]
> 
> Unless you want to propose to include Twisted into the stdlib, this is
> not going to be ready for inclusion into Python 3.2.

I don't think anyone has suggested "include Twisted".  What is being suggested
is "include twisted.internet.defer, or something about as useful."

Let's consider just how hard it would be to just adding
twisted/internet/defer.py to the stdlib (possibly as 'deferred.py').  It's
already almost a standalone module, especially if pared back to just the
Deferred class and maybe one or two of the most useful helpers (e.g.
gatherResults, to take a list of Deferreds and turn them into a single Deferred
that fires when they have all fired).

The two most problematic dependencies would be:

 1) twisted.python.log, which for these purposes could be replaced with a call
    to a user-replaceable hook whenever an unhandled error occurs (similiar to
    sys.excepthook).
 2) twisted.python.failure... this one is harder.  As glyph said, it provides
    "an object that represent[s] an exception as raised at a particular point,
    associated with a particular stack".  But also, as he said, it's a mess and
    could use a clean up.  Cleaning it up or thinking of a simpler replacement
    is not insurmountable, but probably too ambitious for Python 3.2's schedule.

My point is that adding the Deferred abstraction to the stdlib is a *much*
smaller and more reasonable proposition than "include Twisted."

-Andrew.