Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!news2.arglkargh.de!news.albasani.net!rt.uk.eu.org!newsfeed.xs4all.nl!newsfeed2a.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 0.008 X-Spam-Evidence: '*H*': 0.98; '*S*': 0.00; 'expressions': 0.07; 'nested': 0.07; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'though...': 0.09; 'python': 0.11; 'nesting': 0.16; 'possible?': 0.16; 'received:80.91.229.3': 0.16; 'received:dip0.t-ipconnect.de': 0.16; 'received:plane.gmane.org': 0.16; 'received:t-ipconnect.de': 0.16; 'subject:expression': 0.16; 'subject:regular': 0.16; 'wrote:': 0.18; 'wed,': 0.18; 'header :User-Agent:1': 0.23; 'parse': 0.24; 'header:X-Complaints-To:1': 0.27; 'chris': 0.29; 'am,': 0.29; 'easy,': 0.31; 'allows': 0.31; 'regular': 0.32; 'subject:from': 0.34; "can't": 0.35; 'something': 0.35; 'there': 0.35; 'should': 0.36; 'to:addr:python-list': 0.38; 'to:addr:python.org': 0.39; 'received:org': 0.40; 'even': 0.60; 'expression': 0.60; 'more': 0.64; 'subject:Get': 0.68; 'limit': 0.70; 'jul': 0.74; 'upper': 0.74; '100': 0.79; 'otten': 0.84; 'subject:groups': 0.84 X-Injected-Via-Gmane: http://gmane.org/ To: python-list@python.org From: Peter Otten <__peter__@web.de> Subject: Re: Get named groups from a regular expression Date: Tue, 01 Jul 2014 21:00:53 +0200 Organization: None References: Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7Bit X-Gmane-NNTP-Posting-Host: p57bdb5e7.dip0.t-ipconnect.de User-Agent: KNode/4.11.5 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: 15 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1404241273 news.xs4all.nl 2956 [2001:888:2000:d::a6]:51489 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:73806 Chris Angelico wrote: > On Wed, Jul 2, 2014 at 1:29 AM, Peter Otten <__peter__@web.de> wrote: >> Easy, just write a regular expression to parse regular expressions ;) > > Hmm, is that even possible? AIUI you can't make a regex that correctly > parses nested tokens, and named groups can definitely be nested. Hmm, it was a joke. For a limited number of nestings you should be able to cook something up; I think Python allows up to 100 groups, so there is an upper limit of nesting levels. You might need a regex implementation that allows more than 100 groups to parse your regex-parsing regex though...