220 16953 <104b02bf-a3bc-495a-870e-9af9e1ec1fdf@isocpp.org> article Path: news.gmane.org!not-for-mail From: Cleiton Santoia Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Token based access to private members in reflection Date: Thu, 12 Mar 2015 16:22:15 -0700 (PDT) Lines: 263 Approved: news@gmane.org Message-ID: <104b02bf-a3bc-495a-870e-9af9e1ec1fdf@isocpp.org> References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_92_390065066.1426202535546" X-Trace: ger.gmane.org 1426202538 17047 80.91.229.3 (12 Mar 2015 23:22:18 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 12 Mar 2015 23:22:18 +0000 (UTC) Cc: inkwizytoryankes@gmail.com To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCBMVWMTUUNBBKF7RCUAKGQECNNQP6A@isocpp.org Fri Mar 13 00:22:18 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yk0-f200.google.com ([209.85.160.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1YWCQj-0000gA-TG for gclcip-std-proposals@m.gmane.org; Fri, 13 Mar 2015 00:22:18 +0100 Original-Received: by ykbq200 with SMTP id q200sf67382920ykb.3 for ; Thu, 12 Mar 2015 16:22:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:content-type:x-original-sender:reply-to:precedence :mailing-list:list-id:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=qEQjWWj4gdwOMB5O1oNNYdJbWQOE8DiWDT6KnGz8waA=; b=cHKwikPN/mkRYNQZR6YNq2VJDeP6Ro49WEBSmQWeid7CA12LqicWFXVFaZUzGg60xf kWZMXO1YWLTWzgDXaO4IfTmwCqadg7/eoZA4T43MFNMgWBxGGPygKaV81p4zwEum4q0r ZZ7pUDy8fOVJuWHB3J5Clj3OPkURxxCv0igdQDc5zNTCxuRQjVl+q+ii4tuPpPDFqPcp Ux8NLHV7ARcEMO9UghwHkK4r7dLyBl7omrLbzj2tbZmiQylGCabWWpHba7ytyjr0Gjlm xdgq2KfSkQ5t7RZLBh0B2Znaam0fpC8mhwHvl2f7s897FpduoqJi0UBBI4T4KmPfwfvm zVYQ== 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:cc:message-id:in-reply-to :references:subject:mime-version:content-type:x-original-sender :reply-to:precedence:mailing-list:list-id:list-post:list-help :list-archive:list-subscribe:list-unsubscribe; bh=qEQjWWj4gdwOMB5O1oNNYdJbWQOE8DiWDT6KnGz8waA=; b=WDxrUJ2CyIflsBWcccjiRQ6YYUmrmC+XoPJ97B0NnfwO7X31V0o8ANefhcjXq9sRp9 aT92GuSKnA0mC4fVpav0sWlyG0Sugs4ZPUIIkNug5wRxG5ubjVOpxJ3ilZAD8Gz1B/aU lYjpqPn2xk0LE6cwCRzztiWflcBL41RvD2NAVxBFHs8Y+xkIySMupBBnOzXdZyyhqYW3 RiziQxGoGy37saEg5e3zWUbcJrGy5SkYDxWbXjUuJquN+Us92rB+SFZ3Bx5TaM92QgCB RN+2ZNFM2DtreABgOgADpM78vGHS5ODYCk5v70E6q6l5MTZF2yCGk3T5MkrLpJelJI1v nCoA== X-Gm-Message-State: ALoCoQlYa5lBEX99IkGOzxBiIEBpBGTSP9e0bTYz9KQBIR+JLPpOdXSH3LQf0XDjwqbHS+jFS0x6 X-Received: by 10.236.207.230 with SMTP id n66mr45090874yho.30.1426202536726; Thu, 12 Mar 2015 16:22:16 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.18.102 with SMTP id 93ls1366014qge.54.gmail; Thu, 12 Mar 2015 16:22:15 -0700 (PDT) X-Received: by 10.140.91.10 with SMTP id y10mr726573qgd.39.1426202535955; Thu, 12 Mar 2015 16:22:15 -0700 (PDT) In-Reply-To: X-Original-Sender: cleitonsantoia@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:16953 Archived-At: ------=_Part_92_390065066.1426202535546 Content-Type: multipart/alternative; boundary="----=_Part_93_1703473618.1426202535547" ------=_Part_93_1703473618.1426202535547 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable In this document http://random.m-ou.se/reflectionfeedbackurbana.html yo= u=20 will find : Opt-in to unsafe reflection from the class under reflection: SFFNASA543102 Em quinta-feira, 12 de mar=C3=A7o de 2015 19:46:29 UTC-3, inkwizyt...@gmail= ..com=20 escreveu: > > I have idea of system that could be used of handling private data in=20 > reflection. > > First one, we add new template > template > class private_access_token > { > using type =3D /* undefined */; > friend T; > }; > > > And we add to `class_member::pointer` (like from n4113) new default=20 > parameter: > template > struct pointer > { > private: //this line depend if I'th member is private > constexpr static SomeType T::* value =3D /* something */; > friend T; > }; > > template > struct pointer::type > > { > public: //always public with token > constexpr static SomeType T::* value =3D /* something */; > friend T; > }; > > > > > Thanks to that, class implementation can have control over private access= =20 > and allow sharing it to third party libraries without exposing private=20 > fields to the wild. > Some class designer could even allow every one using it by exposing type= =20 > form token: > class A > { > int a; > public: > using PrivateToken =3D private_access_token::type; > }; > > class B > { > int a; > int b; > public: > std::string to_string() { return third_party_func ::type>(this); } > }; > > > > Do you think that could be good solution for that? > > > --=20 ---=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. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposa= ls/. ------=_Part_93_1703473618.1426202535547 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable





Opt-in to unsaf= e reflection from the class under reflection:

=
SFFNASA
543102


=

Em quinta-feira, 12 de mar=C3=A7o de 2015 19:46:29 UTC-3, inkwizyt= ....@gmail.com escreveu:
I have idea of system that could be used of handling private dat= a in reflection.

First one, we add new template
template<typename T>
class private_access_tok= en
{=
    using type =3D /* undefined */= ;
  &n= bsp; friend T;=
};<= br>


And we add to `class_member::pointer` = (like from n4113) new default parameter:
templat= e<ty= pename T, size_t I, token =3D void>
struct pointer
{
private: //this line depend if I'th member is private
    constex= pr stat= ic Some= Type T:= :* value =3D /= * something */;
    friend T;
};

template<typename= T, size_t I&g= t;
s= truct pointer<T, I= , typen= ame private_access_token<T>::type >
{
public: //always public with = token
    constexpr static SomeType T::* value =3D /* something */;
    friend T;
};




Thanks to that, class implementation can have control over pr= ivate access and allow sharing it to third party libraries without exposing= private fields to the wild.
Some class designer could even allow every = one using it by exposing type form token:
class<= /span> A
{<= /span>
    int a;
public:
    using PrivateToken =3D private_access_token<A>::type;
};

class B
{
    int a;
    <= /span>int b;
public:
    std::string to_string() { return third_party_func<private_access_token<B>::type>(this); }
};



Do you think that could be good solution for that?


--

---
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_93_1703473618.1426202535547-- ------=_Part_92_390065066.1426202535546-- .