[pypy-dev] Question from an old friend of mine ....

Armin Rigo arigo at tunes.org
Tue Nov 18 11:10:37 CET 2003

Hi Laura,

On Thu, Nov 06, 2003 at 02:40:54AM +0100, Laura Creighton wrote:
> My friend Geoff Collyer just read the PyPy proposal.
> He said this:
> It appears that compiler theory has advanced quite a bit while I
> wasn't looking.  How much of what you propose has already been
> implemented at least once?  How much of the rest (unimplemented) is
> covered by existing compiler theory?

Sorry for not having answered this one earlier.  I don't know much more about
it than what is written in the proposal, and even there, much was Samuele's
contribution.  All I can say is that probably all bits we describe there have
been already implemented here and there, I just don't think they have all been
put together anywhere.

Object spaces are abstract interpretation domains (though I don't know of any 
regular interpreter that can also do abstract interpretation just by changing 
the domain).

Using an Object space for control flow analysis is probably not new but not 
widely used either.

RPython and the static compilation to C is like R-Scheme, though we do it a
bit differently.  As far as I know our annotation-based type system is novel.  
The start of the theory for it is in trunk/doc/translator/annotation.txt :-)

Weaving aspects at translation-time, like adding Stacklessness or
GC-vs-refcount, is the spirit of aspect-oriented programming, but the latter
has gone in different directions nowadays (which I find quite sad,
independently of PyPy).  But Stackless and GC systems themselves have been
around for a long time, it's just the method to get them which is new.  The
same can be said about Psyco (though not the "long time" bit).

A bientot,


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