[Python-ideas] Make py.exe default to Python 3

[Oscar Benjamin]

On 15 March 2016 at 04:47, Nick Coghlan <ncoghlan at gmail.com> wrote:
> On 15 March 2016 at 09:01, Paul Moore <p.f.moore at gmail.com> wrote:
>> I apologise if I gave the impression in this thread that there's any
>> sort of "official" change in advice on how to launch Python. As far as
>> I know, there hasn't been.

You don't need to apologise in any case but that's not what I meant.
Also I'm not disagreeing with your proposal to change the default
behaviour of py.exe.

It's not so much "official policy" that I was lamenting but just the
way things have evolved. I don't think that anyone really intended to
reach the current situation where the different OSes have diverged and
there's no longer a clear uniform command line to run a Python script.

> It's still "python" - that works regardless of version on Windows
> (with a suitably configured PATH), in virtual environments and in
> pyenv and conda environments (and probably in Enthought Canopy as
> well, but I haven't checked that). The only places where it doesn't
> work are:
>
> * Windows without a properly configured PATH (and without a tool like
> vex or conda)

AFAICT the default behaviour of the Windows installer does not add
Python to PATH. Correct me if I'm wrong as I haven't used it myself
for some time but when I tell my students to "install Python 3.5" and
then to type "python" in the terminal a lot of the Windows users come
back to me with PATH problems (specifically that python was not added
to PATH).

> * accessing Python 3 on *nix systems (without a tool like vex, pyenv or conda)
>
> On the *nix side of things, the long term objective is to get "python"
> to a point of being usable for the latter case, but there's still a
> lot of other things to be done before that's a realistic option (e.g.
> migrating system packages over to using their own dedicated binary or
> symlink, so "python" can be switched to point to something else
> without affecting system services).

Well that would initially improve things but what happens when python
4 comes around? Really I think that for something like this having
major-versioned executables is a good idea. It's just a shame that it
wasn't done consistently.

--
Oscar