Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder1.news.weretis.net!feeder.erje.net!eu.feeder.erje.net!xlned.com!feeder5.xlned.com!newsfeed.xs4all.nl!newsfeed1.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.000 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'url:pypi': 0.03; 'base.': 0.05; 'only,': 0.07; 'pypi': 0.07; 'versions.': 0.07; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'subject:module': 0.09; 'python': 0.11; '2.7': 0.14; '"unit': 0.16; 'code?': 0.16; 'finney': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'targeting': 0.16; 'prevent': 0.16; 'ignore': 0.16; 'code.': 0.18; 'written': 0.21; 'tests': 0.22; 'header:User-Agent:1': 0.23; 'library,': 0.24; 'earlier': 0.24; 'header:X-Complaints-To:1': 0.27; 'converting': 0.30; 'code': 0.31; "d'aprano": 0.31; 'steven': 0.31; 'writes:': 0.31; 'url:python': 0.33; 'older': 0.33; "i'd": 0.34; 'problem': 0.35; 'tool': 0.35; 'but': 0.35; 'url:org': 0.36; 'should': 0.36; 'unit': 0.37; 'ben': 0.38; 'to:addr:python-list': 0.38; 'does': 0.39; 'supporting': 0.39; 'to:addr:python.org': 0.39; 'received:org': 0.40; 'how': 0.40; 'easy': 0.60; 'other.': 0.75; '3.4': 0.84; 'fare': 0.84 X-Injected-Via-Gmane: http://gmane.org/ To: python-list@python.org From: Ben Finney Subject: Re: Maintaining a backported module Date: Thu, 24 Oct 2013 21:01:51 +1100 References: <5268a818$0$30000$c3e8da3$5496439d@news.astraweb.com> <5268ea9b$0$2838$c3e8da3$76491128@news.astraweb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Gmane-NNTP-Posting-Host: rasputin.madmonks.org X-Public-Key-ID: 0xAC128405 X-Public-Key-Fingerprint: 517C F14B B2F3 98B0 CB35 4855 B8B2 4C06 AC12 8405 X-Public-Key-URL: http://www.benfinney.id.au/contact/bfinney-gpg.asc X-Post-From: Ben Finney User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.4 (gnu/linux) Cancel-Lock: sha1:eM4f7HnI4PhvVNEua0PF+z1KbGk= X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 32 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1382608923 news.xs4all.nl 15876 [2001:888:2000:d::a6]:48440 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:57442 Steven D'Aprano writes: > 1) statistics.py in the standard library, which is written for > Python 3.3/3.4 only, and should be as clean as possible; > > 2) a backport of it, on PyPI, which will support older Pythons, and > may be slower/uglier if need be. > > My problem is not supporting 2.7 and 3.4 in the one code base. My > problem is, how do I prevent #1 and #2 from gradually diverging? Generate one of them automatically from the other. My recommendation would be to edit only the code written for Python 3.4, have a fully-automatic generator for the code targeting Python 2.7, and ignore all earlier versions. How does the “3to2” tool fare with converting your code? > The easy answer is "unit tests", but the unit tests for 1) are in the > std lib and target 3.4, while the unit tests for 2) will be on PyPI > and won't. So how do I keep the unit tests from diverging? Again, I'd recommend you generate the Python 2 code automatically from the actively-maintained Python 3 code. -- \ “Beware of and eschew pompous prolixity.” —Charles A. Beardsley | `\ | _o__) | Ben Finney