220 35137 article Path: news.gmane.org!.POSTED!not-for-mail From: Ville Voutilainen Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Add .emplace() method to std::unique_ptr and std::shared_ptr like it is in std::optional. 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[209.85.220.41]) by mx.google.com with SMTPS id p54sor5715640otc.86.2017.10.30.09.06.46 for (Google Transport Security); Mon, 30 Oct 2017 09:06:46 -0700 (PDT) Received-SPF: pass (google.com: domain of ville.voutilainen@gmail.com designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; X-Received: by 10.157.83.6 with SMTP id g6mr6645944oth.432.1509379606425; Mon, 30 Oct 2017 09:06:46 -0700 (PDT) Original-Received: by 10.157.6.16 with HTTP; Mon, 30 Oct 2017 09:06:45 -0700 (PDT) In-Reply-To: X-Original-Sender: ville.voutilainen@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=NnWWgi9c; spf=pass (google.com: domain of ville.voutilainen@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=ville.voutilainen@gmail.com; dmarc=pass (p=NONE sp=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:35137 Archived-At: On 30 October 2017 at 18:05, wrote: > Perhaps being a nice substitution for "= make_...(...)" the return type > should be the reference to smart pointer and the return value should be > *this. The idea looks reasonable enough to me that I would recommend writing a proposal for it. > > On Monday, October 30, 2017 at 8:01:25 PM UTC+4, anta...@gmail.com wrote: >> >> I've found really helpful in my own smart pointer classes to have >> something like .create(Args &&..args) method that creates an object for an >> owning shared pointer without the necessity for repeating the type in the >> make_* non-member function. >> >> It's a shame that standard smart pointers don't have such method, so in >> order to create a value you always need to repeat the type name, while it is >> contained in the pointer type itself. >> >> After that I realized, that std::optional<> has such method named >> .emplace() together with a free function make_optional<>. In some way >> std::optional<> is a lot like "in-place std::unique_ptr<>" with deep-copying >> by default. >> >> So I thought that proposing a member function "ptr.emplace(Args&&... >> args)" for both std::unique_ptr and std::shared_ptr will be a really good >> idea, it will also fit well with std::optional. The naive (but working) >> implementation would be just: >> >> void(?) unique_ptr::emplace(Args &&... args) { *this = >> make_unique(std::forward(args)...); } >> void(?) shared_ptr::emplace(Args &&... args) { *this = >> make_shared(std::forward(args)...); } >> >> What do you think? Are there reasons not to add such methods? Or was this >> discussed / proposed already? >> >> Vasilii Babich. > > -- > 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/db8aed18-d3b3-4df6-8e15-15f8c50e4bed%40isocpp.org. -- 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/CAFk2RUaq1T6tMwAwsdkyorNM8gt550mYRwWkWGWa6gX4a%3D7koQ%40mail.gmail.com. .