Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder1.news.weretis.net!feeder.erje.net!eu.feeder.erje.net!newsfeed.freenet.ag!news2.euro.net!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 0.002 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'patterns': 0.04; 'cache': 0.05; 'class,': 0.07; 'used.': 0.07; 'python': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'subject:Help': 0.10; 'suggest': 0.11; 'yet.': 0.13; '"use': 0.16; 'instance:': 0.16; 'no-nonsense': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'subject:Singleton': 0.16; 'underscores': 0.16; 'wrote:': 0.17; 'config': 0.17; 'instance': 0.17; "shouldn't": 0.17; 'module': 0.19; 'sort': 0.21; 'trying': 0.21; 'import': 0.21; 'example': 0.23; "haven't": 0.23; 'header :In-Reply-To:1': 0.25; 'header:User-Agent:1': 0.26; 'module.': 0.27; 'then.': 0.27; 'options': 0.27; 'header:X-Complaints-To:1': 0.28; 'josh': 0.29; 'trigger': 0.29; 'class': 0.29; 'december': 0.32; 'from:addr:yahoo.co.uk': 0.32; 'morning': 0.32; 'to:addr :python-list': 0.33; 'knowledge': 0.33; 'received:org': 0.36; 'but': 0.36; 'subject:with': 0.36; 'thank': 0.36; 'two': 0.37; 'subject:: ': 0.38; 'mark': 0.38; 'skip:o 20': 0.38; 'to:addr:python.org': 0.39; 'header:Received:5': 0.40; 'your': 0.60; 'first': 0.61; 'mentioned': 0.63; 'more': 0.63; 'therefore': 0.65; 'benefit': 0.70; 'answer.': 0.71; 'saw': 0.75; 'gain': 0.79; 'coffee': 0.84; 'configparser': 0.84; 'otten': 0.84; 'subject:skip:S 10': 0.84; 'anywhere,': 0.93 X-Injected-Via-Gmane: http://gmane.org/ To: python-list@python.org From: Mark Lawrence Subject: Re: Help with Singleton SafeConfigParser Date: Sat, 08 Dec 2012 20:23:41 +0000 References: <113bded6-c75f-4322-9703-93420b4c3522@googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Gmane-NNTP-Posting-Host: host-92-22-93-140.as13285.net User-Agent: Mozilla/5.0 (Windows NT 6.0; rv:17.0) Gecko/17.0 Thunderbird/17.0 In-Reply-To: X-Antivirus: avast! (VPS 121208-0, 08/12/2012), Outbound message X-Antivirus-Status: Clean 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: 46 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1354998232 news.xs4all.nl 6924 [2001:888:2000:d::a6]:46168 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:34502 On 08/12/2012 17:48, Josh English wrote: > On Saturday, December 8, 2012 9:40:07 AM UTC-8, Peter Otten wrote: >> >> Two underscores trigger name mangling only in a class, not in a module. >> >> Don't try to hide the Options instance: >> >> # module config.py >> >> import ConfigParser >> >> class Options(ConfigParser.SafeConfigParser): >> >> ... # as above >> >> options = Options() >> >> Then use it elsewhere: >> >> from config import options >> >> options.set("mysection", "myoption", "myvalue") >> >> All but the first import will find the module in the cache (sys.modules) and >> >> therefore the same Options instance will be used. Voilą your no-nonsense >> >> singleton. > > > Ah. I was over-thinking again. I couldn't find an example of this anywhere, and when I saw the tirades against Singletons they mentioned "use modules" but, well, I haven't had my morning coffee yet. I shouldn't even be trying this sort of thing until then. > > Thank you for the simple answer. > > Josh > For the benefit of the OP and others, if you want to gain more knowledge about patterns in Python such as the Singleton, I suggest you use your favourite search engine to find "Alex Martelli Python patterns". -- Cheers. Mark Lawrence.