[arch-general] Python 3 Rationale?

[C Anthony Risinger]

On Wed, Oct 20, 2010 at 10:45 AM, maxc <maxc at me.com> wrote:
>
> There is an excellent post by Guido here, Hilton:
> http://mail.python.org/pipermail/python-3000/2008-February/011910.html
>
> Guido seems to favor using /usr/bin/python3.0 or /usr/bin/python3 and
> /usr/bin/python as symlinks to the respective versions of Python.
>
> 'Perhaps we should only install "python3.0" and not "python".'
>
> We're not here to discussion semantics ofc. :) There is a much broader
> concern which I hope we can address through friendly discourse.

I think you're agreeing with Arch's decision, but it's not clear to
me, so disregard some of the following if that's the case :-)

the link provided clearly demonstrates the symlink/ambiguity of the
`python` name.  I think he just means maybe they shouldn't
create/include the symlink by default.

so, my last attempt to reason with this circular discussion... :-)

ultimately, py3k is here, and is the path forward, regardless of how
long python2.x will be around (many years i'm certain, it works just
fine [maybe some yummy pypy to come too]).  They are both available
simultaneously, and will be for a very long time.  however, if you use
the bare `python` name, expect to adapt/detect the version/etc at
runtime, because you are leaving the environment up to the system.
factor out the various compatibility bits, so they can be selectively
imported based on the version, thus avoiding syntax errors, etc.

the point is that it really, really, really... doesn't matter what
`python` is symlinked to.  developers need to have the competence to
instruct the system appropriately, and construct the environment they
need to function properly.  if you rely on a particular behavior from
a moving target, then your app is already broken.

C Anthony