Backwards Compatibility of Python versions

[Remco Gerlich]

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.

-- 
Remco Gerlich