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[209.85.220.41]) by mx.google.com with SMTPS id 1-v6sor3264365plx.62.2018.03.04.03.21.34 for (Google Transport Security); Sun, 04 Mar 2018 03:21:34 -0800 (PST) Received-SPF: pass (google.com: domain of gasper.azman@gmail.com designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; X-Received: by 2002:a17:902:9343:: with SMTP id g3-v6mr10187333plp.319.1520162493879; Sun, 04 Mar 2018 03:21:33 -0800 (PST) In-Reply-To: X-Original-Sender: gasper.azman@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=bMxj4qf9; spf=pass (google.com: domain of gasper.azman@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=gasper.azman@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=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:37207 Archived-At: --00000000000072dcb30566946956 Content-Type: text/plain; charset="UTF-8" I call copy_qualifiers "like" in the deducing this paper. I plan to propose it in a separate library extension paper along with forward_like. I like your other proposals. Also see the std::type discussion around the std;:identity paper, I forget the number, by Timur. G On Sun, Mar 4, 2018, 10:58 Richard Hodges wrote: > For my part, while I think the general idea is a good one, it seems to me > that you will make a stronger argument if you are able to provide > motivating use-cases to strengthen the argument for each type/template. > > Do you have some examples? > > > > On 4 March 2018 at 07:55, Vincent Reverdy wrote: > >> Hey, >> >> I was starting to think about putting together a proposal to add minor >> helper classes to either type_traits/utility/tuple to help with some of the >> operations done again and again when doing template metaprogramming. >> Here is a list of a few I can think of, but I would have liked to hear >> other suggestions. Names are just indicative, and bikeshedding would happen >> for all of these types. >> >> >> - *std::blank*, defined as an empty struct >> struct blank{}; >> - *std::pack*, to hold a parameter pack of type >> template struct pack{}; >> - *std::convertible*, a type convertible to anything >> struct convertible{template constexpr operator T() const >> noexcept;}; >> - *std::copy_qualifiers*, a type traits copying ref and cv qualifiers >> from one type to another >> template struct copy_qualifiers {using type = /* >> cv-ref qualfiers of From applied to To*/;}; >> >> Other suggestions? >> >> -- >> 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/e3415a75-7e20-48dd-9e24-0e4681f46e53%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/CALvx3hacsACYSq%2Bh7BHNCjZ2rpajbdcBxa8GigKuHnjO79YDyQ%40mail.gmail.com > > . > -- 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/CAANG%3DkWYr4My4ocY37oi-Nk_paCCegG3LtngSz4Lp5SXpAWF8w%40mail.gmail.com. --00000000000072dcb30566946956 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I call copy_qualifiers=C2=A0 "like" in the dedu= cing this paper. I plan to propose it in a separate library extension paper= along with forward_like.

I li= ke your other proposals. Also see the std::type discussion around the std;:= identity paper, I forget the number, by Timur.

<= /div>
G

On Sun, Mar 4, 2018, 10:58 Richard Hodges <hodges.r@gmail.com> wrote:
For my part, while I think the general id= ea is a good one, it seems to me that you will make a stronger argument if = you are able to provide motivating use-cases to strengthen the argument for= each type/template.

Do you have some examples?



On 4 March 2018 at 07:55, Vincent Reverdy <vince.rev@gmail.com> wrote:
Hey,

I was starting to think about putting = together a proposal to add minor helper classes to either type_traits/utili= ty/tuple to help with some of the operations done again and again when doin= g template metaprogramming.
Here is a list of a few I can think of, but = I would have liked to hear other suggestions. Names are just indicative, an= d bikeshedding would happen for all of these types.

  • std::= blank, defined as an empty struct
    struct blank{};
  • std::pack, to hold a param= eter pack of type
    template <class... T> <= /span>struct pack{};
  • std::convertible, a type convertible to anyth= ing
    struct convertible{template = <class T> constexpr operator T() const= noexcept;};
  • std::c= opy_qualifiers, a type traits copying ref and cv qualifiers from one ty= pe to another
    template <class From, class To> struct copy_qualif= iers {using type =3D /* cv-ref qualfiers of F= rom applied to To*/;};

Other suggestions?

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