[ase-users] [EXTERNAL] Python3.5 vs 3.6 support

[Ask Hjorth Larsen]

Am Mi., 26. Feb. 2020 um 01:18 Uhr schrieb Hermes, Eric via ase-users
<ase-users at listserv.fysik.dtu.dk>:
>
> On Tuesday, February 25, 2020 7:16:06 AM PST Ask Hjorth Larsen via ase-users
> wrote:
> > Dear all,
> >
> > Do you think we should switch to requiring Python3.6+ instead of
> > Python3.5+ as now?  Python3.6 has f-strings, insertion-ordered dicts,
> > and important improvements to type annotations.
>
> So, insertion-order dicts are considered an "implementation detail" in Python
> 3.6. It's only an official language feature in Python 3.7+. Practically
> speaking, this may be a distinction without a difference, but generally I
> think we ought not to rely on "unofficial" behavior like this.

In our case we are in the clear:  We only support CPython, and the
insertion ordering is now a historical fact of CPython 3.6.

If we supported other Python implementations such as Jython,
IronPython, or PyPy, it would not have been okay until 3.7.

>
> That said, I would very much like to rely on insertion-order dicts, because I
> think that may make it easier to generate IO routines for codes where order
> matters.
>
> Maybe we can move to Python 3.7 in 2029 when CentOS 8 reaches EOL :)
>
> Or, maybe we can just look at pypi.org statistics to see which version of
> Python our users are using.

That would be interesting.  Do you know how to get the stats?

Best regards
Ask