Path: csiph.com!usenet.pasdenom.info!aioe.org!news.stack.nl!newsfeed.xs4all.nl!newsfeed4.news.xs4all.nl!xs4all!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 0.015 X-Spam-Evidence: '*H*': 0.97; '*S*': 0.00; 'argument': 0.05; 'cpython': 0.05; 'exist,': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'def': 0.12; 'jan': 0.12; 'created.': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'reedy': 0.16; 'wrote:': 0.18; 'variable': 0.18; 'module': 0.19; '>>>': 0.22; 'python?': 0.22; 'header:User-Agent:1': 0.23; 'case.': 0.24; 'helpful': 0.24; 'header:X-Complaints-To:1': 0.27; 'header:In-Reply-To:1': 0.27; 'function': 0.29; 'correct': 0.29; 'chris': 0.29; 'am,': 0.29; 'raise': 0.29; 'lines': 0.31; '(although': 0.31; 'slot': 0.31; 'not.': 0.33; 'no,': 0.35; 'but': 0.35; 'there': 0.35; 'words,': 0.36; 'two': 0.37; 'to:addr:python- list': 0.38; 'fact': 0.38; 'pm,': 0.38; 'does': 0.39; 'sure': 0.39; 'to:addr:python.org': 0.39; 'either': 0.39; 'received:org': 0.40; 'skip:u 10': 0.60; 'tell': 0.60; 'received:173': 0.61; 'simple': 0.61; 'name': 0.63; 'more': 0.64; 'note:': 0.66; 'compliant': 0.68; 'detail.': 0.68; 'sound': 0.68; 'ethan': 0.84; 'furman': 0.84; 'received:fios.verizon.net': 0.84 X-Injected-Via-Gmane: http://gmane.org/ To: python-list@python.org From: Terry Reedy Subject: Re: Values and objects Date: Sat, 10 May 2014 16:16:34 -0400 References: <235C4BFA-9770-481A-9FCF-21C3F036769C@gmail.com> <5368681D.8070602@islandtraining.com> <87ppjpwafk.fsf@elektro.pacujo.net> <536ad8f2$0$29965$c3e8da3$5496439d@news.astraweb.com> <87zjiqbmy5.fsf@elektro.pacujo.net> <536d7a7d$0$29980$c3e8da3$5496439d@news.astraweb.com> <9cc0ebf9-dbed-4d3d-91fc-2abb9b0103d0@googlegroups.com> <536dc3f7$0$29980$c3e8da3$5496439d@news.astraweb.com> <536decca$0$29980$c3e8da3$5496439d@news.astraweb.com> <536E799D.6080602@stoneleaf.us> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Gmane-NNTP-Posting-Host: pool-173-75-254-207.phlapa.fios.verizon.net User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 In-Reply-To: <536E799D.6080602@stoneleaf.us> 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: 39 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1399753025 news.xs4all.nl 2913 [2001:888:2000:d::a6]:52793 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:71272 On 5/10/2014 3:10 PM, Ethan Furman wrote: > On 05/10/2014 02:32 AM, Chris Angelico wrote: >> >> Tell me, what may this function do in a compliant Python? >> >> def demo(): >> ret = spam >> spam = 23 >> return ret >> >> In CPython, that'll raise UnboundLocalError, Note: >>> issubclass(UnboundLocalError, NameError) True I am not sure if adding the specificity is helpful or not. >> because the local >> variable 'spam' does already exist, and currently has no value (no >> object bound to it). > > No, it does not exist -- or, more accurately, it does not exist *yet* > but will. The fact that there is a slot waiting for what will be spam > is a cpython implementation detail. > > And if you don't like that argument (although it is a perfectly sound > and correct argument), think of the module name space: > > ret = spam > spam = 23 > > will net you a simple NameError, because spam has not yet been created. In other words, those two lines raise a NameError in either case. -- Terry Jan Reedy