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From: Martin v. Loewis on 8 Jul 2010 01:01
> The point, one more time with feeling, is that the incompatibilities
> between 2.x and 3.x will *increase* over time.
I think this is unfounded, and actually false.
Instead, the incompatibilities will *decrease* over the next few years.
Suppose you support 2.x and 3.x from a single code base. Today, you
might support 2.3 up to 3.1. In a year, you might drop 2.3, and start
support 3.2. That will lead to a reduction of incompatibilities: you
can start using 2.4 features, and drop work-arounds for 2.3 limitations.
Likewise when you then, later, drop 2.4.
As a specific example, since 2.5, the modules in the email package are
in lower case, in compliance with PEP 8. 2.x has backwards compatibility
so that you can continue to use the uppercase module names, which you
need for 2.3/2.4 compat. In 3.x, you can't use these spelling anymore,
so your code might use try/except as a work-around. When you drop 2.4,
you can drop the work-around.
> If you now have a code base that is relatively easy to maintain for both
> Python 2.x and 3.x, that is a result of much back-porting efforts and of
> a new-feature moratorium that is currently in effect. Enjoy that
> situation as you may, because it is guaranteed not to last.
On the contrary: it's getting better. The back-porting efforts only
become available in 2.6, and you would have to support at least 2.5
today (at least, that's how many maintainers feel). Only when you
can drop 2.5 support, you can actually start *using* these backport
features, allowing you to make the 2.x and 3.x code more similar.
Eventually, the difference will get larger again. Hopefully, by that
time, 2.7 got out of use.
From: Ben Finney on 8 Jul 2010 03:43
"Martin v. Loewis" <martin(a)v.loewis.de> writes:
> > The point, one more time with feeling, is that the incompatibilities
> > between 2.x and 3.x will *increase* over time.
> I think this is unfounded, and actually false.
Since many other people have responded with similar sentiments, I can
only think I must have been expressing myself very poorly today. I agree
with everything you say here, but it doesn't go against what I've been
If I cared about the issue more, I might have another crack at putting
my meaning into words; but those who want to support a broad stride of
Python versions are more motivated than I to figure it out, so instead I
depart the field.
\ “People's Front To Reunite Gondwanaland: Stop the Laurasian |
`\ Separatist Movement!” —wiredog, http://kuro5hin.org/ |