Overview Slides

Demos:
 - simple pypy-c prompt
 - pypy-cli windows forms demo
 - reflective object space (test_add)


Status:

 - Last year's developments:
   - cleanups:
     - getting rid of unmaintainable features
     - unicode support in RPython

   - a much better GC, generational
   - a ctypes implementation
   - .NET integration

 - cleanups:
   - over the EU project a lot of features accumulated that were required by our proposal
   - not all of them were implemented well
   - all of them were unmaintained
   - they were preventing progress in other areas
   - so we killed them
   - many other improvements on all levels, e.g. RPython support for Unicode

 - ctypes:
   - CTypes is a libffi wrapper for CPython
   - implemented in C
   - can be used to wrap C libraries rather effortlessly
   - CTypes implementation for PyPy:
     - two parts
     - a very thin wrapper around libffi
     - normal Python code for all the CTypes logic
     - some things missing but already very useful
     - ... demo

 - GCs:
   - completely written in Python
   - similar to the MMTK toolkit of Jikes RVM
   - two fast GCs: semispace, generational
   - lots of care to get the semantics right, e.g. of weakrefs and finalizers
   - performance pretty good, memory-bound benchmarks faster than CPython
     despite our bigger memory needs
   - demo (id(x))

 - Currently Working on: JIT Generation
   - writing good JITs for dynamic languages is hard work
   - not really many good JITs around:
     - Psyco (unmaintained)
     - LuaJit (slightly simpler language, genius at work)
     - Tamarin (company support, who knows how good it is)

   - keeping up with new language features is hard
   - compilers are a bad encoding for languag semantics
   - idea: automatically generate the JIT from an interpreter

 - JIT Generation Ideas
   - partial evaluation: old idea from CS research
   - usually in a static compiler context
   - never worked well on real-life examples
   - key insight: things become *easier* if you generate JITs instead of static compilers

 - JIT Generation: Current Status
   - a working prototype at the end of the EU project
   - speeds up simple arithmetic functions *a lot*
   - had limitations that were hard to fix with the design
   - refactoring happened in the last two months to improve the situation
   - still in progress, but already allows experimentation
   - starting to hit the hard bits
   - we hope to get really good results for more general code in a few months
   - demo