[Python-Dev] Bring new features to older python versions

[Maciej Fijalkowski]

On Sat, Oct 8, 2011 at 8:35 PM, "Martin v. Löwis" <martin at v.loewis.de> wrote:
>> The first one is about licensing.
>> What I would be doing is basically copy&  paste pieces of the python
>> stdlib modules (including tests) and, where needed, adjust them so
>> that they work with older python versions.
>> Would this represent problem?
>
> You have a "nonexclusive, royalty-free, world-wide license to ..."
> "prepare derivative works, distribute, and otherwise use Python alone or in
> any derivative version," so: no, this is no problem ...
>
> "provided, however, that PSF's License Agreement and PSF's notice of
> copyright, i.e., "Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007,
> 2008, 2009, 2010, 2011 Python Software Foundation; All Rights Reserved" are
> retained in Python alone or in any derivative version prepared by Licensee."
>
>> My second doubt is about morality.
>> Although this might be useful to those people who are forced to use
>> older python versions, on the other hand it might represent an
>> incentive for not upgrading (and there will be python 3.X features as
>> well).
>
> Don't worry about that. I'm not sure how many people would be interested
> in your approach in the first place - if I have to support old versions
> of Python, I personally just don't use newer features, and don't even
> have the desire to do so. If I want to use newer features, I decide to
> drop support for older versions. That I get both with a hack as such
> a module is just something that I *personally* would never consider
> (there are other reasons for me to consider hacks like this, such as when
> supporting multiple versions is just not feasible, but I wouldn't
> use a hack for convenience reasons).
>
> People that do feel the same way as you have probably started their
> own emulation layers already, so by publishing your emulation layer,
> it's not getting worse.
>
> Regards,
> Martin

Most programs I know have it's own imperfect version of such thing, so
I would definitely use it. Not everyone can drop support for older
versions of python at will.

Cheers,
fijal