220 37147 article Path: news.gmane.org!.POSTED!not-for-mail From: John Yates Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Range-based for: emplace construction of the range expression? 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[209.85.220.41]) by mx.google.com with SMTPS id u143sor1416401vkb.231.2018.03.01.05.55.41 for (Google Transport Security); Thu, 01 Mar 2018 05:55:41 -0800 (PST) Received-SPF: pass (google.com: domain of john.yates.sheets@gmail.com designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; X-Received: by 10.31.100.10 with SMTP id y10mr1164733vkb.55.1519912541398; Thu, 01 Mar 2018 05:55:41 -0800 (PST) Original-Sender: john.yates.sheets@gmail.com Original-Received: by 10.31.155.65 with HTTP; Thu, 1 Mar 2018 05:55:40 -0800 (PST) X-Original-Sender: john.yates.sheets@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=LPDgMpFc; spf=pass (google.com: domain of john.yates.sheets@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=john.yates.sheets@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:37147 Archived-At: --94eb2c0cf7b41eac6205665a37eb Content-Type: text/plain; charset="UTF-8" Recently I have written a class to be used as the range expression in range-based for loops. Buried 4 levels within my new class is a tiny leaf object with RAII semantics. I have been happily using that object unchanged for years. Now my new range class is causing me to have to add move semantics not only to that tiny leaf class but also the 3 new classes layered above it. As best as I can tell this is triggered by the fact that throughout the evolution of range-base for the expansion has always included initialization the hidden range variable via assignment. If the range-expression is an invocation of a constructor then is there any reason that the language could not mandate emplace construction? /john -- 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/CAJnXXogM%3DQ_OUA2806gwbNtPiQ9f2G8KD49VOXteKB7UWKxUrw%40mail.gmail.com. --94eb2c0cf7b41eac6205665a37eb Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Recently I have written a class to be used as the range= expression in range-based for loops.=C2=A0 Buried 4 levels within my new c= lass is a tiny leaf object with RAII semantics.=C2=A0 I have been happily u= sing that object unchanged for years.

Now my new range= class is causing me to have to add move semantics not only to that tiny le= af class but also the 3 new classes layered above it.=C2=A0 As best as I ca= n tell this is triggered by the fact that throughout the evolution of range= -base for the expansion has always included initialization the hidden range= variable via assignment.=C2=A0 If the range-expression is an invocation of= a constructor then is there any reason that the language could not mandate= emplace construction?

/john

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