Path: csiph.com!usenet.pasdenom.info!gegeweb.org!de-l.enfer-du-nord.net!feeder2.enfer-du-nord.net!feeds.phibee-telecom.net!newsfeed.xs4all.nl!newsfeed2.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 0.003 X-Spam-Evidence: '*H*': 0.99; '*S*': 0.00; 'scripts': 0.03; 'explicitly': 0.05; 'caller': 0.09; 'default.': 0.09; 'option,': 0.09; 'subject:Why': 0.09; 'subject:module': 0.09; 'belongs': 0.16; 'command-line': 0.16; 'from:addr:mrabarnett.plus.com': 0.16; 'from:addr:python': 0.16; 'from:name:mrab': 0.16; 'make,': 0.16; 'message-id:@mrabarnett.plus.com': 0.16; 'ought': 0.16; 'really?': 0.16; 'subject:argparse': 0.16; 'wrote:': 0.18; 'library': 0.18; '>>>': 0.22; 'code,': 0.22; 'header:User-Agent:1': 0.23; 'config': 0.24; 'parse': 0.24; "shouldn't": 0.24; 'header:In-Reply-To:1': 0.27; 'raise': 0.29; 'easier': 0.31; '-0700,': 0.31; "d'aprano": 0.31; 'libraries': 0.31; 'steven': 0.31; 'framework': 0.33; 'fri,': 0.33; 'subject:the': 0.34; 'could': 0.34; 'but': 0.35; 'subject:?': 0.36; 'should': 0.36; 'application': 0.37; 'to:addr :python-list': 0.38; 'pm,': 0.38; 'to:addr:python.org': 0.39; 'catch': 0.60; 'happen': 0.63; 'header:Reply-To:1': 0.67; 'invalid': 0.68; 'reply-to:no real name:2**0': 0.71; 'ethan': 0.84; 'furman': 0.84; 'reply-to:addr:python.org': 0.84; '2013': 0.98 X-CM-Score: 0.00 X-CNFS-Analysis: v=2.1 cv=KrN0hwmN c=1 sm=1 tr=0 a=0nF1XD0wxitMEM03M9B4ZQ==:117 a=0nF1XD0wxitMEM03M9B4ZQ==:17 a=0Bzu9jTXAAAA:8 a=K2DDQYBT4xIA:10 a=I0cP0X-GMOAA:10 a=ihvODaAuJD4A:10 a=OUOv7kDek9cA:10 a=8nJEP1OIZ-IA:10 a=EBOSESyhAAAA:8 a=8AHkEIZyAAAA:8 a=_UKPi1JAgJMA:10 a=iXfIMg4ta-QLx9ELufwA:9 a=wPNLvfGTeEIA:10 X-AUTH: mrabarnett:2500 Date: Sat, 29 Jun 2013 16:58:42 +0100 From: MRAB User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 MIME-Version: 1.0 To: python-list@python.org Subject: Re: Why is the argparse module so inflexible? References: <51CC42E3.3070508@gmail.com> <51ccc190$0$29999$c3e8da3$5496439d@news.astraweb.com> <51ce708f$0$29999$c3e8da3$5496439d@news.astraweb.com> In-Reply-To: <51ce708f$0$29999$c3e8da3$5496439d@news.astraweb.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: python-list@python.org 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: 1372521698 news.xs4all.nl 15899 [2001:888:2000:d::a6]:53385 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:49429 On 29/06/2013 06:28, Steven D'Aprano wrote: > On Fri, 28 Jun 2013 18:36:37 -0700, Ethan Furman wrote: > >> On 06/27/2013 03:49 PM, Steven D'Aprano wrote: >>> >>> [rant] >>> I think it is lousy design for a framework like argparse to raise a >>> custom ArgumentError in one part of the code, only to catch it >>> elsewhere and call sys.exit. At the very least, that OUGHT TO BE A >>> CONFIG OPTION, and OFF BY DEFAULT. > > [emphasis added] > >>> Libraries should not call sys.exit, or raise SystemExit. Whether to >>> quit or not is not the library's decision to make, that decision >>> belongs to the application layer. Yes, the application could always >>> catch SystemExit, but it shouldn't have to. >> >> So a library that is explicitly designed to make command-line scripts >> easier and friendlier should quit with a traceback? >> >> Really? > > Yes, really. > [snip] +1 It's the job of argparse to parse the arguments. What should happen if they're invalid is for its caller to decide.