Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder4.news.weretis.net!feeds.phibee-telecom.net!newsfeed.xs4all.nl!newsfeed4.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 0.020 X-Spam-Evidence: '*H*': 0.96; '*S*': 0.00; 'syntax': 0.04; 'string': 0.09; 'agree,': 0.09; 'forcing': 0.09; 'okay': 0.09; 'cc:addr :python-list': 0.11; 'python': 0.11; 'creates': 0.14; 'from:addr:rosuav': 0.16; 'from:name:chris angelico': 0.16; 'parentheses': 0.16; 'tuple': 0.16; 'tuples,': 0.16; 'sat,': 0.16; ':-)': 0.16; 'fix': 0.17; 'wrote:': 0.18; "python's": 0.19; 'cc:addr:python.org': 0.22; 'error': 0.23; 'integer': 0.24; 'cc:2**0': 0.24; 'compare': 0.26; 'right.': 0.26; 'header:In- Reply-To:1': 0.27; 'message-id:@mail.gmail.com': 0.30; "i'm": 0.30; 'that.': 0.31; "d'aprano": 0.31; 'exceptions': 0.31; 'grouping': 0.31; 'steven': 0.31; 'this.': 0.32; 'another': 0.32; 'sense': 0.34; 'could': 0.34; 'subject:with': 0.35; 'agree': 0.35; 'but': 0.35; 'received:google.com': 0.35; 'consistent': 0.36; 'false': 0.36; 'right?': 0.36; 'pm,': 0.38; 'that,': 0.38; 'does': 0.39; 'moving': 0.39; 'how': 0.40; 'remove': 0.60; 'catch': 0.60; 'truly': 0.60; 'worth': 0.66; 'here': 0.66; '2015': 0.84; 'alternative.': 0.84; 'confusing': 0.84; 'different.': 0.84; 'everything.': 0.84; 'subject:..': 0.84; '9:00': 0.91; 'to:none': 0.92 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:cc :content-type; bh=ZENIgiwSaclMb4a/MG56THUvN7x8FNZQ6k50S4mRHEc=; b=WtrkC+2lgYbOVPyiw4W5PNMeafVAYCKjjM3jHBRLk47zUl52O+P4ReFLDRZBGaNngn 11CM4wIHcxn8Yl8h4t8ucNarQZ65/d4UXkTkWGK/WhkMAPhLZkrJZYdXXWx4oogvQux0 TEYrLIiNCl8YxZtfq3pvQFzxCT4WxxDevAqdgG38JGXgkK9XeUMvbSk769PkCw0h61lw E1YH7X8pi9m7/FcdHhq3bxLNmCz6nHA38HhBkK/UEkRDcNgmJfag00gyYG7iQsGMbjb3 7qdE+Z3FgJWdmcomysJnnbp93xqX6kahuuESjpezLPbmx+7hk2YlITGsgEUV0ynOc6d9 oXQw== MIME-Version: 1.0 X-Received: by 10.42.90.208 with SMTP id l16mr8728190icm.59.1428751260945; Sat, 11 Apr 2015 04:21:00 -0700 (PDT) In-Reply-To: <5528feec$0$13002$c3e8da3$5496439d@news.astraweb.com> References: <5528feec$0$13002$c3e8da3$5496439d@news.astraweb.com> Date: Sat, 11 Apr 2015 21:21:00 +1000 Subject: Re: try..except with empty exceptions From: Chris Angelico Cc: "python-list@python.org" Content-Type: text/plain; charset=UTF-8 X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.20 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: 31 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1428751263 news.xs4all.nl 2895 [2001:888:2000:d::a6]:59145 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:88819 On Sat, Apr 11, 2015 at 9:00 PM, Steven D'Aprano wrote: > Yes, I agree that Python's behaviour here is better than the alternative. > Having "except ()" catch nothing is consistent with the behaviour with > other tuples, so I'm okay with that. But it still surprised me :-) It's worth noting that there's another false parallel here. Grouping nothing creates something. x = 1 # x is an integer x = (1) # ditto x = (((((((((1))))))))) # LITHP Okay, so adding parentheses does nothing, right? Right. x = # syntax error x = () # empty tuple "Parentheses around nothing" is NOT the same as "nothing". So if you compare against this, then it makes perfect sense for "except :" and "except ():" to be distinctly different. But I agree, it would be very nice if Python 3 could have abolished the truly confusing part of this, where "except:" catches everything. Forcing people to spell it "except BaseException:" would fix all of this. How hard is it to deprecate and then remove that, same as string exceptions were removed? You know what, I'm moving that to -ideas. ChrisA