extradoc / sprintinfo / pycon06 / sprint-report.txt

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Post-PyCon 2006 Sprint Report

After PyCon this year, we held four days of sprints, from 27th of
February to the 2nd of March 2006.  There were lots of people new to
PyPy and a couple of old friends we hadn't seen for a while.

Here is the list of people participating in the sprint:

  * Gene Oden
  * Bob Ippolito
  * Josh Gilbert
  * Geroge Paci
  * Pat Maupin
  * Martin Blais
  * Stuart Williams
  * Jiwon Seo
  * Michael Twomey (Mick)
  * Anders Lehmann (Anders)
  * Nik Haldimann
  * Samuele Pedronis
  * Armin Rigo
  * Michael Hudson (Michael)
  * Wanja Saatkamp
  * Beatrice Düring
  * Anders Chrigstrom (Arre)
  * Richard Emslie
  * (Christian Tismer -- worked mostly on stackless)
  * (Holger Krekel -- was unfortunately ill for most of the sprint)

Not all people participated for the full sprint; attendance generally
tailed off over the course of the four days.

The announced goals for the sprint were:

  - Work on an 'rctypes' module aiming at letting us use a ctypes
    implementation of an extension module from the compiled pypy-c.

  - Writing ctypes implementations of modules to be used by the above

  - Experimenting with different garbage collection strategies.

  - Implementing Python 2.5 features in PyPy

  - Implementation of constraints solvers and integration of dataflow
    variables to PyPy.

  - Implement new features and improve the 'py' lib and py.test 
    which are heavily used by PyPy (doctests/test selection/...).

  - Generally experiment with PyPy -- for example, play with
    transparent distribution of objects or coroutines and stackless
    features at application level.

Day 1

Monday began with a 45 minute introduction/tutorial by Michael (which
was videoed -- watch for it arriving on codespeak soon-ish) and then a
planning session, where we divided up into pairs or threes and decided
what we'd be working on for the rest of the day.

Armin and three PyPy newcomers -- Mick, Gene and Joshua -- dived into
the ever popular rctypes. They worked on annotation for all ctypes
types. This turned out to involve implementing a new registry
mechanism for external functions, which also will let us eliminate
some of the approximately 42 steps required to add a new external

The two Canadian newcomers -- Stuart and Martin -- got introduced to
PyPy by Arre, implementing the new 2.5 builtins any() and all().  Then
they went on to implementing conditional expressions which, despite
some parser/compiler hairiness, apparently went quite smoothly.

Anders L. and George took a tour of the logic programming facilities
in PyPy and worked on a Sudoku solver using the computation space, but
they were slowed down quite a bit by bugs. The code was not checked in
until after the sprint.

Richard and Pat -- who was hooked on PyPy at the Amsterdam sprint back
in 2003 -- hacked the LLVM backend back into shape (it was broken due
to ongoing work in the GC area). Various compatibility issues with
LLVM versions were also tackled.

Samuele and Nik picked up the lately neglected ootypesystem and
ported PBC tests over from lltypesystem, fixing various loose ends
like __init__ and keyword arguments support.

We should not forget the py.lib sub-sprint happening in the same room
as the PyPy sprint, starring Holger, Jan and Brian. Unfortunately the
Texas Mystery Disease was making the rounds, and both Holger and Brian
weren't feeling well so there was only a little progress, generally
improving the py.lib's story on win32.

Day 2

The Tuesday began with a status meeting where we talked about what
we'd acheived the day before and basically decided that most of us
would carry on with the same things.

Armin, Mick and Gene, having broken all the rctypes tests the day
before, started to use the new 'extregistry' to get things to start
working again.

Nik, Michael and Samuele continued to move rtyper tests from being
lltypesystem-only to running on both typesystems, and implementing the
support thus required in the ootypesystem.  The hardest part off this
was supporting class attributes, as this is not something we assume
the to-be-targeted supports natively (this wasn't finished until

Arre, Stuart and Anders implemented more Python 2.5 features, in
particular those described by PEP 343.

Bob and Richard played with the LLVM JIT.  The hardest part of this
seemed to be working out which libraries to link against...

Later in the day Moshe and Michael played around with the stackless
features, in particular coroutines, and in the end made their play
into a new test.

Day 3

By Wednesday, the sprint was thinning out, but a fair amount of work
still got done.

Samuele and Nik finished off and merged the short-lived ooclassattrs
branch, sorted out some exception issues and moved on to the feared topic
of 'specialized methods' -- when one method in the input source
becomes more than one method in the backend's view.  This didn't turn
out to be as bad as suspected, and by the end of the day the main thing the
ootypesystem lacked was an actual backend...

Richard took Michael on a quick tour of LLVM and then they both worked
on adding support for the various offset types to LLVM, a prerequisite
for LLVM being able to use the framework GCs.

Armin and Gene worked more on rctypes, using the work of the previous
two days to make it work again in a nicer and hopefully more
sustainable way than before.

Anders, Stuart and Arre worked on more Python 2.5 PEPs, finishing the
343 work and generally tidying some things up.

In the afternoon, Michael compiled a fresh Python from SVN HEAD (many
many new features had been implemented by the Python code sprint in
the room next door) and attempted to run the PyPy test suite with it.
This uncovered a number of problems both in PyPy and in Python, some
of which were easier to fix than others.

Day 4

The sprinters who had lasted this long were mostly in shutdown mode by
now, with many of them flying out in the afternoon. There wasn't any
formal planning meeting. Some code was written anyway: Armin worked on
SpaceOperation.cleanup; Gene and Armin on rctypes specialization;
Samuele and Nik on __del__ support for ootypesystem; Arre, Anders
L. and Stuart on making the parser and compiler translatable again;
and Richard on running LLVM tests with the isolate tool.

Most people left during the afternoon. The remaining handful hung out
at the hotel pool and were later joined by people from other sprints
for a beer and pizza session. The PyCon organizers even pointed a
wireless router from one of their hotel rooms at the pool, for those
who couldn't stop sprinting even at 9 pm, lying in a deck chair,
typing single-handedly since one hand was clasping a beer ...

We'll be back next year!