[Python-Dev] RELEASED Python 3.0 final

[rdmurray at bitdance.com]

On Sat, 6 Dec 2008 at 20:19, glyph at divmod.com wrote:
> On 05:54 pm, guido at python.org wrote:
>> On Fri, Dec 5, 2008 at 9:28 PM,  <glyph at divmod.com> wrote:
>> Whenever someone asks me which version to use, I alwasys respond with
>> a question -- what do you want to use it for?
>
> In the longer term, I think that you should look at this as a symptom of a 
> problem.  If you learn Java, you learn the most recent version.  If you need 
> your software to work with an older version, you just pass a special option

Sometimes this even works.  But it isn't always easy to get it right,
and if you are mixing libraries....well, in my real-world experience we
wound up upgrading the VM.

> to the compiler.  If you want your *old* software to work with a *new* 
> version, it basically just does (at least, 99% of the time).

If you specify the source option correctly.

It seems to me that 3to2 and 2to3 are the python equivalent to the javac
'target' and 'source' options.  Like Guido said, the python community
just doesn't have the resources to make them perfect :(.

Based on a quick google, the Java community appears to be grappling
with these same issues:

     http://blog.adjective.org/post/2008/02/21/Java-Backwards-Compatability

the poster seems intent on maintaining more backward compatibility
than we have with python2/3, until you remember that java uses a
compile-and-distribute-binaries paradigm and python does not.  Once you
realize that, the differences in backward compatibility don't
seem so large...at least to me.

--RDM