[Stackless] Re: [Zope-dev] Zope 2.7 running with Stackless 3.0

Bob Ippolito bob at redivi.com
Wed Sep 3 23:19:04 CEST 2003


On Wednesday, Sep 3, 2003, at 16:12 America/New_York, Jim Bowery wrote:

> Someone who thinks there should be more allowance for indeterminate 
> order of evaluation in highly threaded applications.

Twisted ( http://www.twistedmatrix.com/ - website might still be moving 
though ) does this to an extent with Deferreds (aka promises/futures, I 
think), but it's based on a single threaded reactor pattern (with 
threads/threadpools if you need them for specific tasks) and doesn't 
have the luxury of stackless to speed up and simplify things.  Each 
Deferred object is a chain of callback/failure pairs, but they're not 
transparent.  Acquiring the value or failure from a Deferred is only 
possible through the callback/errback callback chain, it will never 
morph into the value object if you try and use it like one (not 
transparent).  This is good and bad, but it can be done with mainline 
Python without new syntax or even generators (when you use generators 
with Deferreds you pretty much go back to synchronized land, so they're 
not good for much other than syntax in Twisted).

-bob
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