220 15305 article Path: news.gmane.org!not-for-mail From: Ville Voutilainen Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Isn't it time we had the bool std::[container]::contains() family of methods? Date: Thu, 25 Dec 2014 21:08:17 +0200 Lines: 71 Approved: news@gmane.org Message-ID: References: <0959f2f8-acdd-4786-b6f3-0f05c62dcee6@isocpp.org> <1fbcb132-f6ca-4dbf-b5ef-f114447faf8c@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1419534505 5101 80.91.229.3 (25 Dec 2014 19:08:25 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 25 Dec 2014 19:08:25 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC5JHI7A7ALRBIWB6GSAKGQEWOFEGTA@isocpp.org Thu Dec 25 20:08:20 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-vc0-f199.google.com ([209.85.220.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Y4Dlj-0005wa-PZ for gclcip-std-proposals@m.gmane.org; Thu, 25 Dec 2014 20:08:19 +0100 Original-Received: by mail-vc0-f199.google.com with SMTP id le20sf28013874vcb.2 for ; Thu, 25 Dec 2014 11:08:18 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:content-type:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe; bh=u4HIkp4KTjN2vdJw9iwGVrPo8xkHHap50du9NUfoSIE=; b=lDdZXG8vxK7iEv57xDMAbF40EkxfbIYuQPKtaxhZGuKCNbfC3UZpzReKXWbcpGrZgl d2aWdXiEqfjWPZpCO3lE3DWirT4DRUWeVDky2eU1BvN+pwFL1v3dQClOqlhYhINmYEPa 1S7V6IRJDvK1+73phxWeLBCG/SXvpSLUFg8ylGnLYm0kVQE5qGsYtEmv7SxlGRbFd0S0 GUjQp9yNFPEzPRfgnjVadvXyxvzGq/W59MqJdz5uXTxA1tyYCQluRk/QQCsuG/7bveNt NUWH/32ltp6pFvXjCUM33UvfNoie+wTQHxdGnOP7+/Ri1l3BxEFBVZxQkPGIpcFUbDzA dnHQ== X-Gm-Message-State: ALoCoQnBMo3neBO1RyV4mI1CQCYu6UtwcfS5Pgwxmz0hJRGsTSkML9VZMiVsES24LBkO45FVPGIz X-Received: by 10.224.114.144 with SMTP id e16mr14218430qaq.3.1419534498777; Thu, 25 Dec 2014 11:08:18 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.182.128.227 with SMTP id nr3ls2614548obb.18.gmail; Thu, 25 Dec 2014 11:08:18 -0800 (PST) X-Received: by 10.182.42.168 with SMTP id p8mr2187866obl.81.1419534498020; Thu, 25 Dec 2014 11:08:18 -0800 (PST) Original-Received: from mail-oi0-x22f.google.com (mail-oi0-x22f.google.com. [2607:f8b0:4003:c06::22f]) by mx.google.com with ESMTPS id o8si16265967obl.80.2014.12.25.11.08.18 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 25 Dec 2014 11:08:18 -0800 (PST) Received-SPF: pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:4003:c06::22f as permitted sender) client-ip=2607:f8b0:4003:c06::22f; Original-Received: by mail-oi0-f47.google.com with SMTP id v63so20695891oia.6 for ; Thu, 25 Dec 2014 11:08:17 -0800 (PST) X-Received: by 10.202.73.6 with SMTP id w6mr22241848oia.37.1419534497900; Thu, 25 Dec 2014 11:08:17 -0800 (PST) Original-Received: by 10.76.154.2 with HTTP; Thu, 25 Dec 2014 11:08:17 -0800 (PST) In-Reply-To: X-Original-Sender: ville.voutilainen@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:4003:c06::22f as permitted sender) smtp.mail=ville.voutilainen@gmail.com; dkim=pass header.i=@gmail.com; dmarc=pass (p=NONE dis=NONE) header.from=gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:15305 Archived-At: On 25 December 2014 at 21:02, Leo Heinsaar wrote: > Hi Olaf - same argument from me as just wrote to Andy. See http://open-std.org/JTC1/SC22/WG21/docs/papers/2014/n4273.htm and http://open-std.org/JTC1/SC22/WG21/docs/papers/2014/n4280.pdf Having generic operations in the library is good, but it's rather likely that having them as non-member algorithms is somewhat preferred to adding a member to every container. Do remember that legacy arrays do not have member functions (although personally I don't really care). I'm not saying it wouldn't be good to add members that do the same thing for every container and would standardize existing-practice-boilerplate (if (foo.find(whatever)!=foo.end()) gets old after you've written it twice). I'm just saying that it may be a hard sell. ;) > > Thanks, > Leo > > > On Thursday, December 25, 2014 8:44:12 PM UTC+4, Olaf van der Spek wrote: >> >> On Thursday, December 25, 2014 7:40:40 AM UTC+1, Leo Heinsaar wrote: >>> >>> Hi guys, >>> >>> Range-for and auto greatly simplify code dealing with iterators - thanks >>> to all who contributed to that - but don't you think it's an omission we >>> still don't have the very simple bool contains(const T&) family in STL >>> containers? >>> >>> There's hardly a single production codebase in the world that doesn't >>> have the contains() boilerplate (I mean, of course, comparing the result of >>> find() to an end() to see if the value is there), often in multiple places. >>> And I guess range-for and auto were also at least partly born out of >>> realization that our code often deserves a higher abstraction level than >>> iterators. >>> >>> Correct me if I'm wrong, but I see contains() as a not-so-big of an >>> addition to the standard library that would be of quite significant value. >> >> >> Hi Leo, >> >> If it's about maps etc you could use count() or a find wrapper that >> returns a pointer (to second) for simpler syntax. >> contains() might still be useful. >> >> Olaf > > -- > > --- > You received this message because you are subscribed to the Google Groups > "ISO C++ Standard - Future Proposals" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to std-proposals+unsubscribe@isocpp.org. > To post to this group, send email to std-proposals@isocpp.org. > Visit this group at > http://groups.google.com/a/isocpp.org/group/std-proposals/. -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. 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