Backwards emulation rather than backwards compatibility?

[Tim Churches]

Christopher Browne wrote:
> 
> Quoth Tim Churches <tchur at optushome.com.au>:
> > I'm not sure how such a meta-interpreter would deal with already
> > compiled bytecode - is there a version stamp in the bytecode?
> 
> Wouldn't it be easier to simply change the first line to:
> #!/usr/bin/python1.5

Yeah, but what about the value of environment variables such as 
PYTHONPATH, PYTHONSTARTUP and PYTHONHOME? I would want these to be
automatically set to the appropriate values.

On Windows, I gather that these values are read from the Registry
under HKEY_LOCAL_MACHINE/Software/Python 

Tim C