Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.lang.python > #38876

Re: any chance for contracts and invariants in Python?

Path csiph.com!usenet.pasdenom.info!dedibox.gegeweb.org!gegeweb.eu!nntpfeed.proxad.net!proxad.net!feeder1-2.proxad.net!usenet-fr.net!nerim.net!novso.com!news2.euro.net!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Return-Path <ethan@stoneleaf.us>
X-Original-To python-list@python.org
Delivered-To python-list@mail.python.org
X-Spam-Status OK 0.004
X-Spam-Evidence '*H*': 0.99; '*S*': 0.00; 'subject:Python': 0.05; 'definitions': 0.07; 'purpose.': 0.07; 'definition,': 0.09; 'expectation': 0.09; 'from:addr:ethan': 0.09; 'from:addr:stoneleaf.us': 0.09; 'from:name:ethan furman': 0.09; 'inherited': 0.09; 'message-id:@stoneleaf.us': 0.09; 'received:184.172': 0.09; 'received:gator410.hostgator.com': 0.09; 'subclasses': 0.09; '~ethan~': 0.09; 'ignore': 0.13; '10:05': 0.16; 'hierarchy': 0.16; 'traverse': 0.16; 'wrote:': 0.17; 'thu,': 0.17; 'feb': 0.19; 'code.': 0.20; 'ones.': 0.22; 'work,': 0.22; 'errors': 0.23; 'header:In-Reply-To:1': 0.25; 'header:User- Agent:1': 0.26; 'am,': 0.27; 'class': 0.29; 'classes': 0.30; 'call.': 0.30; 'impression': 0.33; 'to:addr:python-list': 0.33; 'requiring': 0.35; 'subject:?': 0.35; 'something': 0.35; 'method': 0.36; 'should': 0.36; 'charset:us-ascii': 0.36; 'option': 0.37; 'subject:: ': 0.38; 'some': 0.38; 'to:addr:python.org': 0.39; 'header:Received:5': 0.40; 'enable': 0.60; 'real': 0.61; 'first': 0.61; 'production': 0.63; 'respect': 0.63; 'choose': 0.65; 'received:67.18': 0.65; 'special': 0.73; 'power': 0.74; '2013': 0.84; 'original.': 0.84; 'subject:any': 0.84; 'to:name:python': 0.84; 'contracts': 0.91; 'serious': 0.98
Date Thu, 14 Feb 2013 10:33:14 -0800
From Ethan Furman <ethan@stoneleaf.us>
User-Agent Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2
MIME-Version 1.0
To Python <python-list@python.org>
Subject Re: any chance for contracts and invariants in Python?
References <70c4a8a5-0e8d-4e5c-b0cd-e4ccd90c5cb3@googlegroups.com> <511D18C8.5040404@phihag.de> <CALwzidnDuqCMOdpmM2doD9EkL6JyOvDsqBZ+xzzMb-pXgD+Hng@mail.gmail.com>
In-Reply-To <CALwzidnDuqCMOdpmM2doD9EkL6JyOvDsqBZ+xzzMb-pXgD+Hng@mail.gmail.com>
Content-Type text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding 7bit
X-AntiAbuse This header was added to track abuse, please include it with any abuse report
X-AntiAbuse Primary Hostname - gator410.hostgator.com
X-AntiAbuse Original Domain - python.org
X-AntiAbuse Originator/Caller UID/GID - [47 12] / [47 12]
X-AntiAbuse Sender Address Domain - stoneleaf.us
X-BWhitelist yes
X-Source
X-Source-Args
X-Source-Dir
X-Source-Sender ([173.12.184.235]) [173.12.184.235]:40218
X-Source-Auth ethan+stoneleaf.us
X-Email-Count 1
X-Source-Cap dG9idWs7dG9idWs7Z2F0b3I0MTAuaG9zdGdhdG9yLmNvbQ==
X-BeenThere python-list@python.org
X-Mailman-Version 2.1.15
Precedence list
List-Id General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe <http://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive <http://mail.python.org/pipermail/python-list/>
List-Post <mailto:python-list@python.org>
List-Help <mailto:python-list-request@python.org?subject=help>
List-Subscribe <http://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups comp.lang.python
Message-ID <mailman.1777.1360867351.2939.python-list@python.org> (permalink)
Lines 28
NNTP-Posting-Host 2001:888:2000:d::a6
X-Trace 1360867351 news.xs4all.nl 6962 [2001:888:2000:d::a6]:58989
X-Complaints-To abuse@xs4all.nl
Xref csiph.com comp.lang.python:38876

Show key headers only | View raw


On 02/14/2013 10:05 AM, Ian Kelly wrote:
> On Thu, Feb 14, 2013 at 10:03 AM, Philipp Hagemeister <phihag@phihag.de> wrote:
>> So any implementation has to choose one of the following:
>>
>> 1. Ignore invariants and postconditions of inherited classes - defeats
>> the purpose.
>> 2. Only respect definitions in classes and methods in the original
>> definition, which would be unpythonic
>> 3. Only respect the "original" definitions, for some value of original.
>> Simarily, this would break monkey patching.
>> 4. Update all subclasses whenever something changes.
>> 5. Traverse the entire class hierarchy for every method call.
>>
>> Which option should be picked?
>
> #5, with the expectation that like assertions the entire machinery
> would be turned off when the -O flag is passed, or perhaps even
> requiring a special flag to enable in the first place.  Contracts and
> invariants would only be used in development work, not in production
> code.

I was under the impression that the real power of contracts was when 
they are /not/ turned off -- the errors we don't catch in development 
are the serious ones.  ;)

--
~Ethan~

Back to comp.lang.python | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

any chance for contracts and invariants in Python? mrkafk@gmail.com - 2013-02-14 03:42 -0800
  Re: any chance for contracts and invariants in Python? Philipp Hagemeister <phihag@phihag.de> - 2013-02-14 18:03 +0100
  Re: any chance for contracts and invariants in Python? Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-14 11:05 -0700
  Re: any chance for contracts and invariants in Python? MRAB <python@mrabarnett.plus.com> - 2013-02-14 18:18 +0000
  Re: any chance for contracts and invariants in Python? Ethan Furman <ethan@stoneleaf.us> - 2013-02-14 10:33 -0800
  Re: any chance for contracts and invariants in Python? Mark Janssen <dreamingforward@gmail.com> - 2013-02-14 18:33 -0800

csiph-web