Collin Winter wrote: > On Nov 12, 2007 12:50 AM, Graham Horler <[EMAIL PROTECTED]> wrote: >> On 12 Nov 2007, 03:24:34, Jan Claeys wrote: >>> Op zondag 11-11-2007 om 17:19 uur [tijdzone -0800], schreef Brett >>> Cannon: >>>> On Nov 11, 2007 4:00 PM, Graham Horler <[EMAIL PROTECTED]> wrote: >>>>> I have been developing in Python since 1.5, and now have to support 2.1 >>>>> as a minimum version. I do like to keep my code runnable on newer >>>>> versions however, and am considering the feasability of forward >>>>> compatibility with Python 3.0. >>>>> >>>>> I also notice the Leo[1] project could use some assistance with forward >>>>> compatibility. >>>>> >>>>> So I was wondering if anyone else had a need for a 2to23.py tool to help >>>>> make code compatible with 3.0 but not break it for 2.x. >>>> What exactly are you proposing? We already have 2to3 >>>> (http://svn.python.org/view/sandbox/trunk/2to3/) for source-to-source >>>> translation from 2.x to 3.0. >>> Graham wants to convert his code such that it works on both Python 2.x >>> (probably even early versions of it?) & Python 3.x. Not 2 instances of >>> code, but one source that works on both 2.x and 3.x... >> Absolutely > > I don't believe that's possible. There are enough key differences > between the two that having the same body of code work in both 2.x and > 3.x would require an extensive, complicated runtime support system > that no-one has all(the ability, the time, the motivation) to > implement. And of course, even if you had such a system, the generated > code wouldn't look anything like well-formed Python and would be a > maintenance nightmare. > Besides which, the migration path is already well-specified: write in 3.x-compatible 2.6 and use 2to3 to migrate the code with no further processing. This does eventually give you a single code base. Earlier versions need not apply - there is no way to accommodate them.
regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
