Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!newsfeed.xs4all.nl!newsfeed2.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; 'from:addr:yahoo.co.uk': 0.04; 'initialize': 0.07; '*args,': 0.09; 'arguments': 0.09; 'expectation': 0.09; 'lawrence': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'python': 0.11; 'language.': 0.14; '"/"': 0.16; '**kwargs)': 0.16; 'before.': 0.16; 'finney': 0.16; 'placeholder': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'url:peps': 0.16; 'language': 0.16; 'wrote:': 0.18; 'code.': 0.18; "python's": 0.19; 'header :User-Agent:1': 0.23; 'url:dev': 0.24; "haven't": 0.24; 'least': 0.26; 'header:X-Complaints-To:1': 0.27; 'header:In-Reply-To:1': 0.27; 'function': 0.29; "doesn't": 0.30; '???': 0.30; "i'm": 0.30; 'that.': 0.31; 'subject:what': 0.31; 'writes:': 0.31; 'url:python': 0.33; 'implemented': 0.33; 'skip:_ 10': 0.34; 'subject:the': 0.34; 'something': 0.35; 'but': 0.35; 'useful': 0.36; 'url:org': 0.36; 'ben': 0.38; 'to:addr:python-list': 0.38; 'to:addr:python.org': 0.39; 'received:org': 0.40; 'our': 0.64; 'more': 0.64; 'holding': 0.65; 'between': 0.67; 'day': 0.76; 'received:2': 0.84; 'subject:self': 0.84 X-Injected-Via-Gmane: http://gmane.org/ To: python-list@python.org From: Mark Lawrence Subject: Re: what is the "/" mean in __init__(self, /, *args, **kwargs) ? Date: Thu, 14 Aug 2014 09:41:05 +0100 References: <53EC1887.6060205@gmail.com> <85iolv7rhr.fsf@benfinney.id.au> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Gmane-NNTP-Posting-Host: host-2-98-207-127.as13285.net User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.0 In-Reply-To: <85iolv7rhr.fsf@benfinney.id.au> 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: 35 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1408005684 news.xs4all.nl 2841 [2001:888:2000:d::a6]:47019 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:76282 On 14/08/2014 03:08, Ben Finney wrote: > luofeiyu writes: > >>>>> help(int.__init__) >> Help on wrapper_descriptor: >> >> __init__(self, /, *args, **kwargs) >> Initialize self. See help(type(self)) for accurate signature. >> >> what is the "/" mean in __init__(self, /, *args, **kwargs) ? > > I don't know, I haven't seen that before. It is confusing. > > At least it is acknowledged (“See [elsewhere] for accurate signature”) > to be unhelpful. > > I suspect this is an artefact of the impedance mismatch between Python > function signatures and the implementation of ‘int’ in C code. The “/” > may be a placeholder for something the C implementation requires but > that Python's function signature expectation doesn't allow. > > Perhaps Python 3's keyword-only arguments may one day help functions > like that get implemented with a more useful signature, but I'm not > holding my breath for that. > Something to do with the Argement Clinic http://legacy.python.org/dev/peps/pep-0436/ ??? -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence