[SciPy-dev] -Qnew option breaks scipy

Robert Kern robert.kern at gmail.com
Sun Apr 30 17:44:55 CDT 2006

Eric Nodwell wrote:
> OK, I'll accept that it's not really a bug (yet).  But I disagree that
> it's something one doesn't need to care about until python 3.x, and I
> disagree even moreso that it's not even possible to deal with this
> until 3.x.  My understanding is that PEP238 has been accepted and is
> final, and the change to division is fully implemented as of 2.2, with
> no further changes to division occuring except the gradual phase-in
> for backwards compatibility.  From the PEP:
> ""
> The -Q command line option takes a string argument that can take
>     four values: "old", "warn", "warnall", or "new".  The default is
>     "old" in Python 2.2 but will change to "warn" in later 2.x
>     versions.
> ""

Sure. If that actually happens, then it would also be an appropriate time to
deal with it. Honestly, I doubt it will; the PEP was written a long time ago,
and Python 3.0 plans have changed significantly since then. It's also reasonably
likely that people will be maintaining a separate 2.x branch in parallel to 3.x
and the 2.x branch certainly won't have default warnings for 3.x features.

My suggestion that it is impossible to write 3.0-compatible code is true; the
full set of features of 3.0 don't exist yet, even in planning. We *could* do
this small part now because this one feature is largely specced out already, but
for little or no benefit. It makes more sense to do it when we do the real
conversion for all of the new 3.0 features.

Robert Kern
robert.kern at gmail.com

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco

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