220 25846 <1f37ba85-fbfe-4a00-97fd-ac9125111bea@isocpp.org> article Path: news.gmane.org!not-for-mail From: Nicol Bolas Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Fixed-size views and spans Date: Sun, 8 May 2016 06:40:38 -0700 (PDT) Lines: 81 Approved: news@gmane.org Message-ID: <1f37ba85-fbfe-4a00-97fd-ac9125111bea@isocpp.org> References: <09bfdbe7-70d9-4d25-9f51-4b79cecfb79f@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_2199_227591671.1462714838609" X-Trace: ger.gmane.org 1462714843 22121 80.91.229.3 (8 May 2016 13:40:43 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 8 May 2016 13:40:43 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCEKFTV6ZUMBBV4DXW4QKGQEAVD47GI@isocpp.org Sun May 08 15:40:43 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-vk0-f70.google.com ([209.85.213.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1azOwr-0005El-MD for gclcip-std-proposals@m.gmane.org; Sun, 08 May 2016 15:40:41 +0200 Original-Received: by mail-vk0-f70.google.com with SMTP id e126sf88215957vkb.2 for ; Sun, 08 May 2016 06:40:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=xQApLGXR8ZesHfG9pwxeEH4C2ZgMN2c554cQM3R+/iQ=; b=whEVFX/Nm7vgIzboAb0crvIDJ6ywC9JWCGSokBFxy6YEXKvfhWhthNyYdDM2vRyMdi Dv6kHvDca9q9MVrtpJeVvTypNJLh++wGCD18CNnw1vPGlmyYvK72TRvb9t05h6Dqvbw5 NmGpPRHGQKGse/5jhGoRN7PCcGZAkETSQaQjql4pDOSB7tc2KooxHuFpe5QfDsFuyxhg yQ1wxBcDsmKWCb8PwAsZgrXJ4Af5pXPcZ5ep4SIuEzqrR/VPVH6cUQdGpDA1Z2ebXMzj D/OXDorO93Mqv/UgfAu35dm0KYyzfpQwgcXwkYGyTwU2ulCCsdmdpUKzhk5rm+xmEUPG EwwQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=xQApLGXR8ZesHfG9pwxeEH4C2ZgMN2c554cQM3R+/iQ=; b=J0gMulJg3DLq1YHJWdOFTncfgqX07Tfqn9reRoNsATJO7fkRsQ5xK4NUec1eE0lYDo s8bcUE8xH//pqKf+AYtNSPlXEgA+9uLHLTxZ7+2bhvxk3YaBfm4fvObTQGQd8/38Bohj 7wg4SVsvl46JG5B8emaUBrOFo0/G+ttgWs7FYwnpifcwBmlBnnqesfBk3SfxVOABoeSk m0A/ZLFrZb1X/kW+ZYSZjFJWsYkE2jCSh1gzsP9o59al2xSTzmucKxoaxQJYuyTDg44x gm6Zia+RDvUHeHeE9Q0MpdQRcKD78flWBcna/2UL6snVCePE2JjHhUigjvPsxtf2r/R6 MzrA== 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:message-id:in-reply-to:references :subject:mime-version:x-original-sender:reply-to:precedence :mailing-list:list-id:x-spam-checked-in-group:list-post:list-help :list-archive:list-subscribe:list-unsubscribe; bh=xQApLGXR8ZesHfG9pwxeEH4C2ZgMN2c554cQM3R+/iQ=; b=Q5/cfKUbIrvJFsY6JuSVQLVvu8eQtDOsVo9MBMrVA4feNdnZhsqutTxTtvEeuAA5tY M6t+dttWSn4gGafzp44Yt1p6k6SM45TQRHyyPhnH72thrVyAqH4bBJHGuRTx4xXblmkv VjTGHoEAVVijTAghrNTUFPlUvUb3lQIV7QbuRfRSnsU8SeGKHnnoCTNwzpsAzxo4pyib pXxZQoYb1Kvdm1xyYGur+bcm80kubG4dP9HWyQ9KA+dAXByrzy6vmaWEHNIc1A9LPteh Wdrpv02c/MFyDSr2fuqp9xY8/p66PcKBrI+PDMnWjfG/yICvR9grocIyCdiD35jauMsS V/2w== X-Gm-Message-State: AOPr4FWn7W+BlMnYSInKgyiSrR19pg2ldF6cbIfRTd3XQoZFUWsRujKYS17qw9d4aDHaWw== X-Received: by 10.140.30.203 with SMTP id d69mr13301270qgd.19.1462714840676; Sun, 08 May 2016 06:40:40 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.3.66 with SMTP id a2ls966829iga.43.gmail; Sun, 08 May 2016 06:40:39 -0700 (PDT) X-Received: by 10.50.182.7 with SMTP id ea7mr71597igc.2.1462714839626; Sun, 08 May 2016 06:40:39 -0700 (PDT) In-Reply-To: <09bfdbe7-70d9-4d25-9f51-4b79cecfb79f@isocpp.org> X-Original-Sender: jmckesson@gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org 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:25846 Archived-At: ------=_Part_2199_227591671.1462714838609 Content-Type: multipart/alternative; boundary="----=_Part_2200_620974199.1462714838610" ------=_Part_2200_620974199.1462714838610 Content-Type: text/plain; charset=UTF-8 The GSL `span` type already supports being compile-time sized. Being dynamically sized is simply a specialization. As for specializations in standard library algorithms... I don't much care for that. Sure, they can be *allowed*, but we shouldn't expect them. First, WikiSort seems to be able to work based solely on random-access iterators. So it's not clear why we would need specializations for that. Also WikiSort appears to have an implicit requirement of `value_type` being default constructible (for the cache), which is not something that `stable_sort` requires. So it could not be a general replacement in the library (though this requirement may merely be lazy programming, not a requirement of the algorithm). Second, if I have a need for the properties of WikiSort, it would be silly of me to just use `stable_sort` and hope that the implementation provides this specializations. Yes, quality-of-implementation matters, but that is simply expecting way too much from your implementation. The standard library is a general tool for general uses; if you need such specific algorithms, then you *need* specific algorithms. I wouldn't be against having a few of these newer sorting algorithms added to the standard library. But they should be new functions which have the explicit behavior of their particular algorithms. -- 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. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/1f37ba85-fbfe-4a00-97fd-ac9125111bea%40isocpp.org. ------=_Part_2200_620974199.1462714838610 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
The GSL `span` type already supports being compile-time si= zed. Being dynamically sized is simply a specialization.

As for spec= ializations in standard library algorithms... I don't much care for tha= t. Sure, they can be allowed, but we shouldn't expect them.
<= br>First, WikiSort seems to be able to work based solely on random-access i= terators. So it's not clear why we would need specializations for that.= Also WikiSort appears to have an implicit requirement of `value_type` bein= g default constructible (for the cache), which is not something that `stabl= e_sort` requires. So it could not be a general replacement in the library (= though this requirement may merely be lazy programming, not a requirement o= f the algorithm).

Second, if I have a need for the properties of Wik= iSort, it would be silly of me to just use `stable_sort` and hope that the = implementation provides this specializations. Yes, quality-of-implementatio= n matters, but that is simply expecting way too much from your implementati= on. The standard library is a general tool for general uses; if you need su= ch specific algorithms, then you need specific algorithms.

I = wouldn't be against having a few of these newer sorting algorithms adde= d to the standard library. But they should be new functions which have the = explicit behavior of their particular algorithms.

--
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