Booleans, integer division, backwards compatibility; where is Python going?

[Terry Reedy]

"Dave Brueck" <dave at pythonapocrypha.com> wrote in message
news:477762c2.0204081003.75867687 at posting.google.com...
> Paul Rubin <phr-n2002a at nightsong.com> wrote in message
news:<7xadshtrj1.fsf at ruckus.brouhaha.com>...
> > Stable doesn't just mean old scripts run without change in new
> > interpreters.  It also means new scripts usually run without
change in
> > old interpreters.
>
> How could that possibly work?

You declare the old interpreter to be bug free -- ie, that its
behavior *is* the (unchanging) specification.  Then you limit yourself
to invisible changes -- ie, those that only change (hopefully reduce)
time and space requirements.  (This allowance requires, of course,
that one define dependencies on running time and size to be outside
the specification and, in a sense, illegitimate.)

Terry J. Reedy