[pypy-dev] question about core implementation language

[logistix]

"Edward K. Ream" <edream at tds.net> wrote: 
> 
> > I have started some prototyping in Python, and I now
> > remember some words of Guido, that Python isn't specially
> > well suited for such a task. I admit, there is some
> > truth in it.
> 
> I don't understand Guido's comment.  I personally think Python is absolutely
> superb for any prototyping endeavor.
> 
> Perhaps I am being dense, but the fact that Python doesn't have feature x of
> language y seems totally a non-issue.  You want a switch statement?  Write a
> psyco_switch function (in Python, of course). Ditto for anything else your
> heart desires.  Eventually _everything_ that generates code is going to
> become assembly code, but that is no problem at all for any compiler.
> 
> Perhaps I am confusing levels of discussion or implementation.  However, the
> way I see it, the most important thing is to do experimentation with
> algorithms.  To do that, the essential thing is to compare various ways of
> doing things, at as high a level as possible.  In other words, a
> psyco_switch routine provides a good enough model for the task at hand.
> Ditto for any other construct you want.
> 
> Actually, for experimentation (perhaps leading to inspiration) I wouldn't
> necessarily confine myself to any particular level of implementation or
> design or whatever.  I would simply blast away using whatever language tools
> appear to be most useful.  Armin has talked about doing high-level work with
> discovering list optimizations, for example.  I don't understand what the
> lack of a Python switch statement has to do with such matters.
> 
> In short, I would hardly bother at all with questions of the level at which
> Python is modeling some implementation.  I would use whatever works in
> Python and worry about mapping that back to a final implementation only
> after it is clear that Python in Python will be a big win.  At that time we
> will have lots more data, energy and incentive to do the needed grunt work.
> Until then, I wouldn't let implementation problems get in the way of
> invention.
> 
> Just my $0.02.
> 
> Edward
> 
> 
> 
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I think the point is that Python as a language provides absolutely no
access to the machine internals.  You can't examine memory contents,
registers, I/O bus or call code directly.  As part of the bootstrap
process the following four functions should probably be added to the
interperter (either as builtin functions or a module):

    GetMemoryFromOS()
    ReturnMemouryToOS()
    Peek()
    Poke()

ANd probably:
    get/putRegister()
    callCode()

Other than that, everything could (eventually) be written in Python.
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