[pypy-dev] Annotating space status

[Guido van Rossum]

Armin ends a long, eloquent and well thought-out message with:

> Drawback: We can only process RPython program. Well, that was the original
> goal anyway. I think it is cleaner but it also means that it will take more
> time before we can actually process the whole of PyPy. The other (current)  
> solution is more like we have a very general but hacky W_Anything() fall-back,
> that could quickly be complete enough to process arbitrary programs (provided
> however that we don't keep running into these mutable object problems, which
> is not clear to me).
> 
> Both goals are interesting per se, but my opinion is that we should
> concentrate on the first one right now.

I would find processing arbitrary programs cooler, and if I had time
to contribute coding time (which I don't) I would want to pursue that.

I think the problems with mutable objects can be fixed entirely by
using deepcopy after each step.  Deepcopying, BTW, ses a memo to keep
track of object identities, so it will preserve the (perhaps useful to
the analysis) knowledge that two W_Anything() objects found in
different local variables or stack positions are in fact the same
object.

But since I don't have time (alas), I think it's fine to pursue the
goals of those who do (like Armin an Samuele) first.

--Guido van Rossum (home page: http://www.python.org/~guido/)