Greetings from an assortment of tired brains at CERN, home to a larger assortment of hopefully less tired physicist brains. We are reaching the end of a succesful and well-attended (24 participants!) sprint. 3.5 days times 24 people is a bit more than two man months of work -- we are going to try to cover all we've achieved, but will undoubtedly forget some stuff! Summer of Code student Lawrence and his mentor Arre spent the majority of the time integrating Lawrence's SoC work -- ctypes implementations of various CPython extension modules -- into PyPy. He has implemented the time, mmap and fcntl modules so far, and the work at this sprint concentrated on putting the time module into the form required for PyPy -- making it a mixed module, conforming to the restrictions of rctypes and fighting the extension compiler. Brian Sutherland and Sad Rejeb also joined in this play, attempting to convert some prewritten performance sensitive caching code used in Zope(!) somewhere to a mixed module suitable for feeding to the extension compiler. Unfortunately the resulting code was no faster than the pure Python version... probably because of the ext-compiler using refcounting for GC. Antonio appeared to spend his entire time writing commit messages but somehow must have written some code in between (with the help of *his* SoC mentor, Armin) because now all of PyPy's Standard Interpreter can be rtyped with the ootypesystem. "All" that remains are the dict implementation and external function support in the CLI backend before IronPython has a competitor in the shape of PyPy.Net :-) Guido (not *that* Guido) being the JavaScript deity he is wrote a JS tool to instrospect the DOM methods and produce useful information for Maciej's SoC (we only had three SoC students here...) project. Unfortunately browsers' JavaScript implementations are famously eccentric and running his tool popped up the Print dialog box twice and then crashed Epiphany. It proved marginally less frustrating to write a scraper for Mozilla's documentation and fix the broken HTML he found there. Aurélien, Ludovic and part of Armin tried to figure out why the example of coroutine cloning written for the "What can PyPy do for you?" talk didn't work. Assorted mind boggling bugs were found and fixed, with the aggravating result that it now works fine when run on the llinterpreter but crashes -- after a while -- when translated to C. More wizardry will be required here... Just before the sprint Maciej attempted to improve the annotator's error messages and he and Samuele spent some time fixing this new code (it's very frustrating when your error printing routines crash on you...). A varying team of people including but not limited to Pieter, Carl Friedrich, Maciej and Alexander worked on alternative, hopefully faster implementations of Python data types, particularly strings and dictionaries. We now have efficient representations of slices of strings and for the result of adding two strings, all completely transparent to application-level. For a sufficiently cooked benchmark, we are now up to seven times faster than CPython (and use 30 times less memory). On the dictionary side, we stole an optimization for CPython: assume on creation that a dictionary will only contain strings keys and switch to an alternative implementation on the insertion of a non-string key. This makes pystone and richards both around 20% faster, some benchmarks up to 40% faster (but also some a few percent slower). Alexandre and David started to think about configuration and option handling, but got distracted when they tried to run a translation on a 64-bit machine (or more specifically, a machine with 64-bit userland), because it broke in obscure ways. A few obscure fixes later and it worked again apart from stackless, and another few fixes fixed that too. Michael and Fabrizio worked on the stackless code, "un-inlining" some of the frame-state saving code with the goal of reducing the size of the generated code. This involved taking Fabrizio on a whirlwind tour of one of the scarier areas of the PyPy codebase, but he survived and the feature was implemented, although the size reduction was not as great as had been hoped -- more investigation required (we also need to build a stacklessgc build to check that). Michael and Fabrizio then worked on AST- and bytecode-level optimizations, which mostly involved building an infrastructure to make modifications of the AST easier. They implemented a simple constant folder at the AST level and at the bytecode level an optimization to remove the temporary tuple in code like "x,y=y,x". Simon and Eric resurrected and experimented more with LLVM's JIT interface. Simon then worked with Ludovic and Arre on implementing RPython support for numarrays and Eric worked on making the output of genc compilable with C++. Guido and Holger implemented the beginning and perhaps the middle but probably not the end of doctest support in py.test. After some discussion with Alexandre, David and Holger, Guido and Carl Friedrich began to work on the rather ugly-looking task of taming pypy's growing menagerie of options. They started to implement a general mechanism for defining a hierarchy of options, handling dependencies and conflicts among them. From this you can generate optparse Options for command line interfaces and will one day be able to generate a web form to choose among the zoo of pypy's options. They used the config mechanisms to de-insane the selection of the various object space variants. This, for example, makes automated testing of the above-mentioned variant string and dictionary implementations possible. Pieter worked on random modules^W^Wthe random module, porting it to RPython and implementing some missing functions. So, after a pre-sprint (for some of us), a conference and a post-sprint, we are well prepared for the usual post-sprint week long sleep. Apart from Carl, he has an exam on Friday. Oops! Met vriendelijke groeten, mwh&cfbolz -- This proposal, if accepted, will probably mean a heck of a lot of work for somebody. But since I don't want it accepted, I don't care. -- Laura Creighton, PEP 666