PyPy - Automatic Generation of VMs for Dynamic Languages

Google Tech Talks
November, 14 2007

In Search of Speed and Flexibility. PyPy and the Art of Generating Virtual Machines

We all want our favorite dynamic language to be faster, to be even more
dynamic and to pick up nifty ideas from its peers.

But this is so much work!

There ought to be a better way to implement dynamic languages that
enables growth and necessary change with less effort and more ease.
Writing yet another interpreter in C or even Java is not it.

PyPy is a framework to implement dynamic languages that embraces this
challenge. It allows us to write such languages in the form of simple
interpreters, expressed in a rich subset of Python. This means that
the resulting implementations can can be evolved with reasonable
effort.

PyPy then generates a variety of virtual machines (VMs) from a single
source. We can therefore target a wide range of environments,
including C/Posix, Java, or .NET. This avoids the major source of
fragmentation within a dynamic language community -- the need for a
separate language implementation for each virtual machine. It also
means that languages as distinct as Python, Prolog and Smalltalk can
share the bulk of our compiler machinery.

The flexible toolchain which is necessary for virtual machine
generation turns out to be good for other things as well. Traditional
implementations for dynamic languages have to make some very hard
decisions early, which then become entrenched in the whole codebase,
making it difficult or impossible to change later. It can be nice to
experiment with different garbage collectors, but not if you have to
write a complete new implementation of your favourite language for
each one. With PyPy you don't have to. You can also generate and
tailor a JIT-compiler for the language at hand, putting to rest the
notion that flexibility must come at the expense of speed.

Speaker: Samuele Pedroni
Speaker: Armin Rigo
Speaker: Jacob Hallén
Speaker: Laura Creighton

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[klined]

pypy is the most ambitious project any language has ever had

[foundtheory]

The majority of the talk (and most interesting parts!) is free of audio problems...

Great talk, a lot of good information on PyPy

[Evi1M4chine]

@klined: LOL, then you’ve never seen an ambitious software project. If you want serious shit, go Haskell! There, every fuckin’ library or language enhancement is so advanced and new, that it just left theory because someone wrote a implementation for his thesis.

And a *scripting language* wants to keep up with that (as can be seen by Python constantly cloning Haskell ideas)... LOL.

This here is at best the inner platform anti-pattern creeping in. (Look it up.) Which is why GHC won’t touch it.

[cybernytrix]

The presentation is totally unimpressive. I also do not believe that they have anyhting that is useful in the real world. There is not way in hell you can write an interpreter in RPython and make it run as fast as CPython or Jython *ever*.  Remember they use JIT, so you must use Psyco to make a fair comparison.

Smoke on...

[collodiallofi]

I do not consider any of the speakers to be remotely hot

[pbrinkhall]

The audio sux!

[robinsto]

After 7 min 30 s, the audio is good.

[polukaks]

actually, the audio is just fine after some initial troubles.

[alunufal]

Very bad audio. Too low and most of the time ininteligible.