220 34963 <58cdd9a2-3f73-4991-8fad-ef753634a4f0@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: Aleksey Loginov Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Idea about "std::pmr::memory_resource" Date: Mon, 16 Oct 2017 05:17:52 -0700 (PDT) Lines: 158 Approved: news@gmane.org Message-ID: <58cdd9a2-3f73-4991-8fad-ef753634a4f0@isocpp.org> References: <0a8293b4-3246-47a5-9881-bc1ca4b91772@isocpp.org> <07ddb1f6-d3af-43df-bf96-8975c1ab4313@isocpp.org> <2e191a96-1952-479b-b78b-22e31f8e03de@isocpp.org> <0e37b5ae-64f6-4a8a-86bd-f44b119ed40a@isocpp.org> <15f8c5ba-3a6a-4441-9620-92e157c66094@isocpp.org> <26fe4cb4-98ca-41cc-ac96-5c51851799d1@isocpp.org> <784ffce8-ace7-449d-a13d-a99d7336117a@isocpp.org> <6d0ad98b-87d5-43dd-ac54-2b7d3e03e31b@isocpp.org> <72ef3209-6749-4246-9c5a-1549557ceb5a@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_168_889624143.1508156272443" X-Trace: blaine.gmane.org 1508156289 26796 195.159.176.226 (16 Oct 2017 12:18:09 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 16 Oct 2017 12:18:09 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCGIDMXA5AJRB4OGSLHQKGQENTRWPQI@isocpp.org Mon Oct 16 14:18:00 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ua0-f197.google.com ([209.85.217.197]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e44L4-0004dY-Rc for gclcip-std-proposals@m.gmane.org; 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Mon, 16 Oct 2017 05:17:54 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.176.72.81 with SMTP id c17ls3373949uad.10.gmail; Mon, 16 Oct 2017 05:17:53 -0700 (PDT) X-Received: by 10.31.153.21 with SMTP id b21mr721854vke.13.1508156273013; Mon, 16 Oct 2017 05:17:53 -0700 (PDT) In-Reply-To: <72ef3209-6749-4246-9c5a-1549557ceb5a@isocpp.org> X-Original-Sender: Aleksey.Loginov@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:34963 Archived-At: ------=_Part_168_889624143.1508156272443 Content-Type: multipart/alternative; boundary="----=_Part_169_690657811.1508156272443" ------=_Part_169_690657811.1508156272443 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =D0=BF=D0=BE=D0=BD=D0=B5=D0=B4=D0=B5=D0=BB=D1=8C=D0=BD=D0=B8=D0=BA, 16 =D0= =BE=D0=BA=D1=82=D1=8F=D0=B1=D1=80=D1=8F 2017 =D0=B3., 14:55:41 UTC+3 =D0=BF= =D0=BE=D0=BB=D1=8C=D0=B7=D0=BE=D0=B2=D0=B0=D1=82=D0=B5=D0=BB=D1=8C Mingxin = Wang=20 =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB: > > On Monday, October 16, 2017 at 6:55:41 PM UTC+8, Aleksey Loginov wrote: > >> Let's look at a more applied example: >> >> template=20 >> struct static_resource : memory_resource { aligned_storage_t m_dat= a >> ; }; >> >> template >> struct my_any; >> >> >> my_any x1; >> my_any> x2; >> >> x1 =3D 1; >> x2 =3D x1; >> >> assert(x2 =3D=3D 1); >> >> >> How can you do this without RTTI? >> > > What is the semantics of `x2 =3D=3D 1`? There is no definition about=20 > `operation=3D=3D(...)` in the class `std::any`, and this expression is=20 > ill-formed if `x2` is a value of `std::any`. Do you mean that=20 > `any::operator=3D=3D(const any&)` shall be added to the standard? If so, = I=20 > suggest that you should illustrate your motivation and provide reasonable= =20 > semantics. > > No, this is just test of result assignment (can be rewritten as any_cast ) Main question is: how you can implement operator=3D without having base=20 *memory_resource *for MR. PS: in standard it will be more useful to get inner_resource in=20 std::memory_resource for chaining (similar to *scoped_allocator_adaptor*) --=20 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 e= mail 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/58cdd9a2-3f73-4991-8fad-ef753634a4f0%40isocpp.or= g. ------=_Part_169_690657811.1508156272443 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


=D0=BF=D0=BE=D0=BD=D0=B5=D0=B4=D0=B5=D0=BB=D1=8C= =D0=BD=D0=B8=D0=BA, 16 =D0=BE=D0=BA=D1=82=D1=8F=D0=B1=D1=80=D1=8F 2017 =D0= =B3., 14:55:41 UTC+3 =D0=BF=D0=BE=D0=BB=D1=8C=D0=B7=D0=BE=D0=B2=D0=B0=D1=82= =D0=B5=D0=BB=D1=8C Mingxin Wang =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB:=
On Monday, Oc= tober 16, 2017 at 6:55:41 PM UTC+8, Aleksey Loginov wrote:
Let's look at a more = applied example:

template<= /span><size= _t Size= >
struct static_resource : memory_resource { <= span style=3D"color:rgb(0,0,0);font-family:DejaVuSansMono,"DejaVu Sans= Mono",courier,monospace;font-size:12.8px;white-space:nowrap;backgroun= d-color:rgb(255,255,255)">aligned_storage_t<Size> m_data; };

template<typename MR<= span style=3D"color:#660">>
= struct=C2=A0my= _any;


my_any<default_= memory_resource> x1;
my_any<static_resource<32>> x2;

x1 =3D 1;
x2 =3D x1;

assert(x2 =3D= =3D 1);


How can you=C2=A0do this without RTTI?

What is the semantics of `x2 =3D=3D= 1`? There is no definition about `operation=3D=3D(...)` in the class `std:= :any`, and this expression is ill-formed if `x2` is a value of `std::any`. = Do you mean that `any::operator=3D=3D(const any&)` shall be added to th= e standard? If so, I suggest that you should illustrate your motivation and= provide reasonable semantics.

=
No, this is just test of result assignment (can be rewritten= as=C2=A0any_cast<x2>)
Main question is: = how you can implement operator=3D without having base=C2=A0memory_resource=C2=A0for MR.<= /span>

PS: in standard it will be more useful to g= et inner_resource in std::memory_resource for chaining (similar to scope= d_allocator_adaptor)

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