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Beta for 1.1.0 released

Today we are releasing a beta of the upcoming PyPy 1.1 release. There are some Windows and OS X issues left that we would like to address between now and the final release but apart from this things should be working. We would appreciate feedback.

The PyPy development team.

PyPy 1.1: Compatibility & Consolidation

Welcome to the PyPy 1.1 release - the first release after the end of EU funding. This release focuses on making PyPy's Python interpreter more compatible with CPython (currently CPython 2.5) and on making the interpreter more stable and bug-free.

PyPy's Getting Started lives at:

Highlights of This Release

Other Changes

What is PyPy?

Technically, PyPy is both a Python interpreter implementation and an advanced compiler, or more precisely a framework for implementing dynamic languages and generating virtual machines for them.

The framework allows for alternative frontends and for alternative backends, currently C, Java and .NET. For our main target "C", we can "mix in" different garbage collectors and threading models, including micro-threads aka "Stackless". The inherent complexity that arises from this ambitious approach is mostly kept away from the Python interpreter implementation, our main frontend.

Socially, PyPy is a collaborative effort of many individuals working together in a distributed and sprint-driven way since 2003. PyPy would not have gotten as far as it has without the coding, feedback and general support from numerous people.

Have fun,

the PyPy release team, [in alphabetical order]

Amaury Forgeot d'Arc, Anders Hammerquist, Antonio Cuni, Armin Rigo, Carl Friedrich Bolz, Christian Tismer, Holger Krekel, Maciek Fijalkowski, Samuele Pedroni

and many others:


Benjamin Peterson wrote on 2009-04-20 01:21:

Congratulations! PyPy is becoming more and more viable every day. I hope I can continue to become more involved in this awesome project.

Anonymous wrote on 2009-04-21 01:18:

pypy is a very interesting project!

i have a question. do you think pypy-c without jit can ever reach the speed of c-python? why is it slower?

or will you put all the optimization efforts into the jit now? doesn't the performance difference matter because the jit will make it up anyway?

Maciej Fijalkowski wrote on 2009-04-21 04:36:

PyPy without jit can (and is sometimes) be faster than cpython, for various reasons, including garbage collector.

On the other hand, we rather won't sacrifice simplicity for speed and we hope that jit will go that part. Also the funny thing is that since we generate our jit, it gets better as interpreter gets simpler, because jit generator is able to find out more on it's own. So in fact we might give up on some optimizations in favor of simplicity, because jit will be happier.


Luis wrote on 2009-04-21 14:04:

Sorry for my anxiety, but is there any rough estimation on when the jit will be in a usable state?

Maciej Fijalkowski wrote on 2009-04-21 22:14:

Personally, I'm doing it in my free time. That means I'm giving no estimates, because it makes no sense. If you wish to go into some contractual obligations on our sides, we're up to discuss I suppose :-)

Luis wrote on 2009-04-21 22:33:

Maciej, I know how hard you are working on this. I didn't mean to sound disrespectful and I don't want to bother you... It's just that as everyone else, I'm anxoiusly looking forward to seeing pypy's magic in action. By the way, the new post is very much appreciated. Thanks!

Anonymous wrote on 2009-06-29 07:47:

I am desperately looking for some help building PyPy. I have posted a an Issue (#443) about my issues in the PyPy site.

If anyone from the release/Dev. team can give me a hand, I would seriously appreciate this!

I can be reached at