220 15371 <34298b73-1e10-4efa-8527-e1caf84c719c@isocpp.org> article Path: news.gmane.org!not-for-mail From: Leo Heinsaar 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: Mon, 29 Dec 2014 11:34:30 -0800 (PST) Lines: 94 Approved: news@gmane.org Message-ID: <34298b73-1e10-4efa-8527-e1caf84c719c@isocpp.org> References: <0959f2f8-acdd-4786-b6f3-0f05c62dcee6@isocpp.org> <1467325.0dEsDvEnHx@tjmaciei-mobl4> <3990670.unDteUsXEa@tjmaciei-mobl4> <232a2f25-0907-48e5-ba04-e1d9b09e19e7@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_632_571036662.1419881670535" X-Trace: ger.gmane.org 1419881680 21100 80.91.229.3 (29 Dec 2014 19:34:40 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 29 Dec 2014 19:34:40 +0000 (UTC) Cc: mw_triad@users.sourceforge.net To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCFYDAXXQYEBBRWZQ2SQKGQEOE62N5I@isocpp.org Mon Dec 29 20:34:34 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pa0-f72.google.com ([209.85.220.72]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Y5g5I-0004p5-Ua for gclcip-std-proposals@m.gmane.org; Mon, 29 Dec 2014 20:34:33 +0100 Original-Received: by mail-pa0-f72.google.com with SMTP id kq14sf111883501pab.11 for ; Mon, 29 Dec 2014 11:34:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:content-type:x-original-sender:reply-to:precedence :mailing-list:list-id:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=nXD7qWMaGj6P/470x6s999GhJzXurta/W5H6AiJnXNA=; b=kiyQb32tr3XjXhvBiE+DMFtLQes3c6RmVBnFjRo324dOulkt7w2mUlP+U+JxDw4D7v 8i2dig+AamD195Vd5lA87RZJLOXIFi1p9Dm9NU61ejIPdT6gXhynYUfHRt14uwgJYQK8 d4ENzN0Dc/+1Ev5zA54DLHY8Y/qKKZZ4U2zgnRXszQED1aJyZYrp27X0oORzhYLfLnie apQVq3A1BygVxBywREhPuj7y1XA6EKO68ZxPKRIY5TDUdCU17/EreLtY1M7FNIvH5jyL UFqM37pl79AaWQMMfaOOEBMnBD6Kxvd3CncRVnnTVvQwnuTV8Xbhqm+eu8yXH1Lg9zRI pCvg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:content-type:x-original-sender :reply-to:precedence:mailing-list:list-id:list-post:list-help :list-archive:list-subscribe:list-unsubscribe; bh=nXD7qWMaGj6P/470x6s999GhJzXurta/W5H6AiJnXNA=; b=B2Sx5nQQ4xve+GEYztYYxNzwO01GrW//knZFAqLlr14kui2+3AErrHn1XkJ5znla2D xdLTotuyNtR3GrPs3Xs3Dp0Ps5ZDizcSaK03Mc+sJNFOeE2A7PWUt8+uWTgFz3o/ork4 Ga+5qCGo2oEfNo+DOZPFvaclTkrXUpEJkkHSYdI7jaulHtSudOzTxvQpMHoelcZ0yXu7 sWDccSADeaSF2JAOIL4vcLHs+rxloweOls1hi8XoDXxYHGnTTF56gFIELWR++52iiuE1 0BfdZxufMpR87QVpK1veu7ols6f9tO9nvxFxoRoZhbltm0QfwutS/z7qb+MSFQUVcKgR V/zg== X-Gm-Message-State: ALoCoQkRC9MwZuXFfRSRizK/KxkhRZadCzgJq1c0XXtbI70AQmgWI7ObYZKCxxzTYz7guKOflk+U X-Received: by 10.66.66.1 with SMTP id b1mr43768365pat.8.1419881671704; Mon, 29 Dec 2014 11:34:31 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.107.181 with SMTP id h50ls7821186qgf.85.gmail; Mon, 29 Dec 2014 11:34:30 -0800 (PST) X-Received: by 10.140.16.55 with SMTP id 52mr17455qga.31.1419881670790; Mon, 29 Dec 2014 11:34:30 -0800 (PST) In-Reply-To: X-Original-Sender: leoheinsaar@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:15371 Archived-At: ------=_Part_632_571036662.1419881670535 Content-Type: multipart/alternative; boundary="----=_Part_633_308759791.1419881670535" ------=_Part_633_308759791.1419881670535 Content-Type: text/plain; charset=UTF-8 On Monday, December 29, 2014 11:26:52 PM UTC+4, Olaf van der Spek wrote: > > On Mon, Dec 29, 2014 at 8:17 PM, Leo Heinsaar > wrote: > >> I can't think what behavior would be introduced that would be > >> surprising; can you please elaborate? > > > > > > On a general note: once we convert something to bool, there is no > stopping > > it from interacting with other fundamental types from short to double. > Just > > seems that for iterators, that might introduce unnecessary type-safety > bugs. > > That's why we've got explicit operator bool. Well, originally, at least, Matthew wrote: "Maybe we could instead create a form of ::find() that returns an optional or checked_iterator or similar, that can be *implicitly* cast to bool to test for validity." But even if it is made explicit, seems like it becomes too verbose to write *static_cast*. Leo -- --- 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/. ------=_Part_633_308759791.1419881670535 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Monday, December 29, 2014 11:26:52 PM UTC+4, Ol= af van der Spek wrote:
On Mon, = Dec 29, 2014 at 8:17 PM, Leo Heinsaar <leohe...@gmail.com> wrote:
>> I can't think what behavior would be introduced that would be
>> surprising; can you please elaborate?
>
>
> On a general note: once we convert something to bool, there is no = stopping
> it from interacting with other fundamental types from short to dou= ble. Just
> seems that for iterators, that might introduce unnecessary type-sa= fety bugs.

That's why we've got explicit operator bool.
 
Well, originally, at least, Matthew wrot= e: "Maybe we could instead create a form of ::find() that returns=20 an optional<iterator> or checked_iterator or similar, that can=20 be implicitly cast to bool to test for validity."

But even if it is made explicit, seems like it becomes too verbose t= o write static_cast<bool>.

Leo

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