first release of PyPy

[Carl Friedrich Bolz]

Hi!

Ville Vainio wrote:
>>>>>>"Torsten" == Torsten Bronger <bronger at physik.rwth-aachen.de> writes:
> 
> 
>     Torsten> What's supposed to be compiled?  Only PyPy itself or also
>     Torsten> the programs it's "interpreting"?
> 
> PyPy is written in python, if it can be compiled then the programs can
> be as well.

That's correct in the sense that if a program adherses to the same 
staticness conditions as the PyPy code, it can be compiled. The core 
parts of the PyPy interpreter are written in "Restricted Python" 
(RPython), which imposes some limits to the features you are allowed to 
use. This is done in such a way that the annotator can perform type 
inference, e.g. you are not allowed to assign values with different 
types to a variable (plus some more restrictions). See

http://codespeak.net/pypy/index.cgi?doc/coding-guide.html#restricted-python

for more details about RPython.

> 
>     Torsten> I've been told by so many books and on-line material that
>     Torsten> Python cannot be compiled (unless you cheat).  So how is
>     Torsten> this possible?
> 
> These guys are exploring a new territory. OTOH, Lisp is a dynamic
> language like python and it can be compiled to native code. Pyrex
> demonstrates the "trivial" way to compile python to native code, the
> real problem is making the resulting code fast. Typically this
> requires type inference (i.e. figuring out the type of an object from
> the context because there are no type declarations) to avoid dict
> lookups in method dispatch.

There is some preliminary documentation about the type infering (which 
is called annotation here) and the translation process:

http://codespeak.net/pypy/index.cgi?doc/translation.html

Regards,

Carl Friedrich