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PyPy 1.2: Preview of Just-in-Time Compilation
=============================================

Welcome to the PyPy 1.2 release.  The highlight of this release is a
version of PyPy that includes a rather good JIT (Just-in-Time) Compiler.

Download page:
    
   http://codespeak.net/pypy/dist/pypy/doc/download.html

PyPy's Getting Started lives at:

   http://codespeak.net/pypy/dist/pypy/doc/getting-started.html

Highlights of This Release
==========================

  - JIT.  XXX only on 32-bit Intel CPUs so far.

    http://morepypy.blogspot.com/search/label/jit

  - Graphs:

    http://speed.pypy.org/
    http://codespeak.net:8099/plotsummary.html
    http://codespeak.net/pypy/jitplots.html

  - Improvements in GC and in our object model: we use much less memory
    than CPython now

    http://morepypy.blogspot.com/2009/10/gc-improvements.html
    http://? for the object model, e.g. sharingdict.py


Other Changes
=============

  - ?

  - CLI+JIT not included in the release

  - Stackless incompatible with the JIT


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 as well as 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.

The focus of this release is the introduction of a new transformation,
the JIT Compiler Generator, which is able to produce a JIT Compiler for
any interpreter frontend, given a very small number of hand-written hints.

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, Antonio Cuni, Armin Rigo, Carl Friedrich Bolz,
    Holger Krekel, Maciek Fijalkowski, Samuele Pedroni

    and many others:
    http://codespeak.net/pypy/dist/pypy/doc/contributor.html