[Stackless] Practical uses of stackless technology

Andrew Francis andrewfr_ice at yahoo.com
Tue Oct 24 18:43:14 CEST 2006

Hello Carl:

(I need to get off the digest format...)

>So this is where we come to you, the >existing
>stackless community: why are you interested in

I have been using Stackless Python to prototype
WS-BPEL processors. WS-BPEL or Web Service Business
Process Execution Language is an OASIS based language
specification for electronic orchestration. What makes
WS-BPEL special is its support for long running
transactions (or LRT). Network and database
transactions that have a long duration (i.e., days)
present special problems. Although Stackless has a bit
of a learning curve, I am very pleased with the
results. Stackless is allowing me to do things that
would be difficult in other environments.

>As some of you might know, the PyPy project is aiming
>at including many of stackless' features into its
>Python interpreter. Most of them are now
>implemented and we're now working on the report we
are >writing for the EU about this part of our work.

I think the pickling of execution state is a
particularly powerful, but misunderstood feature of
Stackless Python. Again, it is my believe that
pickling combined with Python's reflection simplifies
implementing of long running transactions. If these
features were placed in PyPy, I would start using

>Being technical hacker types, we can cope with
>describing the ins and outs of how our code works,
but >are less sure on the motivations for
stackless-style >technologies as used in real-world
applications  :)
>(especially since this part of PyPy is not used for
>any applications yet).

(Funny, I was just talking to one of my professors, a
visiting scholar, from Holland about web services)

For whatever it is worth, I have a computer science
and management background (e-commerce and now
operations management). I believe Python and Stackless
Python can carve out a niche in building next
generation web applications involving electronic
orchestration, for example, automated supply chain

>As well as the more general stackless ideas
(tasklets, >channels, etc) we are interested in
hearing about any >use people are making of the
tasklet pickling >features.

Where do I begin? For instance, I use pickling to
serialise idle BPEL processes that are waiting for
network IO. Think of this as application programming
controlled swapping. I almost have this working to my

>It would be wonderful if we could get some nice
>quotable, attributable snippets, but general ideas
>would also be very welcome.

I am very interested in PyPy. I would be happy to
assist you. You can post here, and/or write me in


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