220 13632 <22e20901-a35f-4956-9b90-e45383aafccc@isocpp.org> article Path: news.gmane.org!not-for-mail From: rhalbersma@gmail.com Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: The view concept Date: Fri, 3 Oct 2014 12:39:44 -0700 (PDT) Lines: 80 Approved: news@gmane.org Message-ID: <22e20901-a35f-4956-9b90-e45383aafccc@isocpp.org> References: <428c47bd-67f2-47d1-98c0-e5ca85698076@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_2488_950410295.1412365184935" X-Trace: ger.gmane.org 1412365193 436 80.91.229.3 (3 Oct 2014 19:39:53 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 3 Oct 2014 19:39:53 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCMYZKMJV4IRBAPXXOQQKGQEPKNXH4Q@isocpp.org Fri Oct 03 21:39:48 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pd0-f199.google.com ([209.85.192.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Xa8hf-0005Xc-I7 for gclcip-std-proposals@m.gmane.org; Fri, 03 Oct 2014 21:39:47 +0200 Original-Received: by mail-pd0-f199.google.com with SMTP id g10sf902070pdj.2 for ; Fri, 03 Oct 2014 12:39:46 -0700 (PDT) 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 :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=a+q1q74jOqElOUtuh6KcLg+Qv4SA78m+dK03fchGGiM=; b=W2YhM4MxGQXKerl+t1nKu9H0GG0qAacBq4O7kRLumm2M3EmLFFyCn/kOUg2pbk/q0U HAI1aVFN6/cgdCby2K/VhpJdymLFHx6tAA7M7nFgDp2ec+ZzX+cNWhH2gcius2xWUrBW mqztvi46wNSXFgFwccLsbZZZKdVoSHE5fMz0zK/VSqqIoAAmWJzfOddSeLxyec5yr7R9 8bdcQn/WIBiM5PTcV+70PrlOeB4Nsd3ulEQQeZgDdVXA5HnMeOo1WIb/NLIYAD1jebXN RYoS2aFbDND6oLEp44iKqGiuOLY6fsRBrNxl9qw+x7Q41LN/LhQbc/7TmFHT0Tq1U4bD 7/JQ== 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:list-post:list-help:list-archive :list-subscribe:list-unsubscribe:content-type; bh=a+q1q74jOqElOUtuh6KcLg+Qv4SA78m+dK03fchGGiM=; b=JnWxt7+x/kpBdQoUZbncAVwI0s6tpaKsx5y+xgkzycpN7UAPLuTwjwRAa4TrN9rm4p vDQHwkutYPhtb6Jv83Ho8ivuWcPeVvtQwNQAuMEHyzOs9iAOh1lRTOWMKiMQuXYR13bx lm9zLvVbyURaf6g8K64DkbAs5lJc/EHaAW7XbjT+ESIsHktI9QUqFPyZQT5IgGhiesu0 CPcKxA1rWHQrWCAmljKNB4Sozj6vZ11k4Pzz1gesjESky5YJehQYox5xYe7LabvjXEgk 7fQ9AniVKfcG3Re+8oirZpnDOs5kqF0uTvd4cgEMZW5F1wXCy8NywRW8w0VzAHSWYIWx plpQ== X-Gm-Message-State: ALoCoQkduX50zTbpOHlWK6ugA9imfFlqP1JZLTP15bLJDf/MTvA1rix+TDhmQuzvumfdVE+2Bu7b X-Received: by 10.66.157.197 with SMTP id wo5mr6156604pab.43.1412365186293; Fri, 03 Oct 2014 12:39:46 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.93.38 with SMTP id c35ls1335628qge.92.gmail; Fri, 03 Oct 2014 12:39:45 -0700 (PDT) X-Received: by 10.140.20.39 with SMTP id 36mr30470qgi.15.1412365185528; Fri, 03 Oct 2014 12:39:45 -0700 (PDT) In-Reply-To: <428c47bd-67f2-47d1-98c0-e5ca85698076@isocpp.org> X-Original-Sender: rhalbersma@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:13632 Archived-At: ------=_Part_2488_950410295.1412365184935 Content-Type: text/plain; charset=UTF-8 On Friday, October 3, 2014 7:40:02 AM UTC+2, Matthew Fioravante wrote: > > With array_view, string_view, and now possibly bitset_view, this view > thing is becoming contagious. > > I think at this stage it makes sense to precisely define exactly what a > view is and how it behaves as a concept. Any kind of view type that is > invented now or in the future should adhere to a set of rules so that they > all have a uniform interface. > Boost.Fusion already has a definition for such a concept ( http://www.boost.org/doc/libs/1_56_0/libs/fusion/doc/html/fusion/view.html ): Views are sequences that do not actually contain data, but instead impart > an alternative presentation over the data from one or more underlying > sequences. Views are proxies. They provide an efficient yet purely > functional way to work on potentially expensive sequence operations. Views > are inherently lazy. Their elements are only computed on demand only when > the elements of the underlying sequence(s) are actually accessed. Views' > lazy nature make them very cheap to copy and be passed around by value. -- --- 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_2488_950410295.1412365184935 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Friday, October 3, 2014 7:40:02 AM UTC+2, Matthew Fiora= vante wrote:
W= ith array_view, string_view, and now possibly bitset_view, this view thing = is becoming contagious.

I think at this stage it makes s= ense to precisely define exactly what a view is and how it behaves as a con= cept. Any kind of view type that is invented now or in the future should ad= here to a set of rules so that they all have a uniform interface.

Boost.Fusion already has a definition fo= r such a concept ( http://www.boost.org/doc/libs/1_56_0/libs/fusion/doc/htm= l/fusion/view.html ): 

Views are sequences that d= o not actually contain data, but instead impart an alternative presentation= over the data from one or more underlying sequences. Views are proxies. Th= ey provide an efficient yet purely functional way to work on potentially ex= pensive sequence operations. Views are inherently lazy. Their elements are = only computed on demand only when the elements of the underlying sequence(s= ) are actually accessed. Views' lazy nature make them very cheap to copy an= d be passed around by value.

--

---
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+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/<= /a>.
------=_Part_2488_950410295.1412365184935-- .