Backwards Compatibility of Python versions

[Steve Holden]

"Remco Gerlich" <scarblac at pino.selwerd.nl> wrote in message
news:slrna5v9io.oqf.scarblac at pino.selwerd.nl...
> Paul Rubin <phr-n2002a at nightsong.com> wrote in comp.lang.python:
> > "Tim Peters" <tim.one at home.com> writes:
> > > > That's the problem--if I don't import future division, my code will
> > > > break in the future, because the // operator isn't supported in the
> > > > present.
> > >
> > > Not so:  introducing "//" was 100% backward-compatible, so isn't
controlled
> > > by __future__.  "//" works out of the box in 2.2, no __future__
required.
> >
> > If I type "3//4" into 1.5.2 or 2.1, I get a SyntaxError exception, so
> > it isn't backwards compatible.
>
> It's a new feature. It's impossible that new features work in old
versions,
> basically by definition. Your idea of backwards compatibility is strange.
>
> However, 1.5.2 programs that use "/" will still work in 2.2 (apart from
> other possible incompatible changes since then).
>
> > > I don't know where you're looking, but 2.2 final was released.
> >
> > I know this, but 2.1.1 was released more recently than 2.2, so the most
> > recent release was in the 2.1 series.
>
> I'm going to release a new version of 0.9 then, tomorrow. Then you'll have
> to claim that's the most recent.
>
> > If the official Python maintainers think they might release a 1.5.3
> > someday, then it's fair to say that the 1.5 series is still current.
> > If they're unlikely to ever release another 1.2.x or 0.9.x, then
> > those versions are not current, even if I release a 1.2.x myself.
>
> The official Python maintainers are working on the next version after 2.2,
> probably 3.0. Other people have released a few bugfix
> releases for people who really need to continue running old versions.
>
As far as I know (and I'm only writing this since the developers are
probably mostly at the Conference Developers Day, whereas  am back home) the
next release is 2.3. The PEP list at http://python.sourceforge.net/peps/ has
no 2.3 release schedule PEP yet, but it does list "PEPs under consideration
for 2.3".

Since 3.0 *will* break backward compatibility, there's going to be a long
slow approach to it, with plenty of whistle stops along the way.

regards
 Steve
--
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