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; 'value,': 0.03; 'default.': 0.07; 'key.': 0.07; 'strings.': 0.07; 'attribute.': 0.09; 'length.': 0.09; 'non-default': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'subclass': 0.09; 'tuple': 0.09; 'jan': 0.11; 'value.': 0.15; '*only*': 0.16; '__new__': 0.16; 'arbitrarily': 0.16; 'keys.': 0.16; 'mapping,': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'reedy': 0.16; 'sentinel': 0.16; 'subject:Mapping': 0.16; 'subject:key': 0.16; 'tuple,': 0.16; 'wrote:': 0.16; 'exists': 0.18; 'all,': 0.20; 'sets': 0.23; 'header:In-Reply-To:1': 0.24; 'header:User-Agent:1': 0.26; 'header:X-Complaints-To:1': 0.26; '(e.g.': 0.27; 'sequence': 0.27; 'specify': 0.27; "skip:' 10": 0.28; 'itself,': 0.29; 'tail': 0.29; 'position.': 0.30; 'items.': 0.33; 'wrap': 0.33; 'could': 0.35; 'text': 0.35; 'false': 0.35; 'list:': 0.35; 'something': 0.35; 'list,': 0.36; 'should': 0.36; 'to:addr:python-list': 0.36; 'pm,': 0.36; 'subject:: ': 0.37; 'two': 0.37; 'method': 0.37; 'say': 0.37; 'received:org': 0.37; 'data': 0.39; 'to:addr:python.org': 0.40; 'subject:with': 0.40; 'special': 0.73; 'alternative.': 0.84; 'received:fios.verizon.net': 0.91; 'choice.': 0.93 X-Injected-Via-Gmane: http://gmane.org/ To: python-list@python.org From: Terry Reedy Subject: Re: Mapping, with sequence as key, wildcard and subsequence matching Date: Thu, 16 Jul 2015 01:27:36 -0400 References: <85k2u0vpis.fsf@benfinney.id.au> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Gmane-NNTP-Posting-Host: pool-98-114-97-173.phlapa.fios.verizon.net User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 In-Reply-To: <85k2u0vpis.fsf@benfinney.id.au> 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: 38 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1437024480 news.xs4all.nl 2888 [2001:888:2000:d::a6]:35507 X-Complaints-To: abuse@xs4all.nl X-Received-Bytes: 4272 X-Received-Body-CRC: 3741398253 Path: csiph.com!usenet.pasdenom.info!news.stben.net!border1.nntp.ams1.giganews.com!nntp.giganews.com!bcyclone03.am1.xlned.com!bcyclone03.am1.xlned.com!newsfeed.xs4all.nl!newsfeed7.news.xs4all.nl!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail Xref: csiph.com comp.lang.python:93896 On 7/15/2015 9:51 PM, Ben Finney wrote: > Howdy all, > > What well-defined data type exists with the following properties: > > * Mapping, key =E2=86=92 value. > > * Each key is a sequence (e.g. `tuple`) of items such as text strings. > > * Items in a key may be the sentinel `ANY` value, which will match any > value at that position. > > * A key may specify that it will match *only* sequences of the same > length. > > * A key may specify that it will match sequences with arbitrarily many > additional unspecified items. Every key should signal which of the last two alterntives holds. One can = be a default. The signal can be 'in-band', in the tuple key itself, or=20 'out-of-band', not in the tuple key. An in-band signal must be a=20 special value, like 'ANY', that is not otherwise used in keys. ...=20 might be a good choice. For out-of-band, you could try a tuple subclass = with a __new__ method that sets an attribute. Or wrap a tuple, say with = a list, to signal the non-default alternative. Something like tail =3D False if type(key) is list: tail =3D True key =3D key.pop() --=20 Terry Jan Reedy