220 22230 <0fcfc169-4076-4569-9089-4bc80e65d469@isocpp.org> article Path: news.gmane.org!not-for-mail From: yannick.daveluy@gmail.com Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Adding virtual/private/protected/public keywords in template parameter Date: Wed, 4 Nov 2015 00:08:38 -0800 (PST) Lines: 168 Approved: news@gmane.org Message-ID: <0fcfc169-4076-4569-9089-4bc80e65d469@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_6106_1051089625.1446624518488" X-Trace: ger.gmane.org 1446624522 5589 80.91.229.3 (4 Nov 2015 08:08:42 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 4 Nov 2015 08:08:42 +0000 (UTC) Cc: yannick.daveluy@gmail.com To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDTMBZFA54HBBB7242YQKGQEUTDFNLA@isocpp.org Wed Nov 04 09:08:42 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ob0-f200.google.com ([209.85.214.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Ztt7Z-0007sm-K8 for gclcip-std-proposals@m.gmane.org; Wed, 04 Nov 2015 09:08:41 +0100 Original-Received: by obbxp9 with SMTP id xp9sf1143840obb.2 for ; Wed, 04 Nov 2015 00:08:40 -0800 (PST) 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:x-spam-checked-in-group:list-post:list-help :list-archive:list-subscribe:list-unsubscribe; bh=3Be6U2q61MfVEI5XjsXNO9Cmk/JNUEcanYQ6K2MH2ak=; b=iF/Wv5cBX9W2s0NCZur7NSGJgtjzAJdXLx6Spr6eNCAassLegqUMAJg7ZRm0f1IjVu 50sb7lKTtI5wLNRzlhjg1WsmZKB9qPh9XfXmQMrQkyYtdursbBtmb2KIQllTm/1U+mj5 m2ypB3NJOAjg0ZuvBj8ch6YodlsCJbBsPhM5kHcN4thECE6I9jGVLeRyrU9B33DJYEdj 9ox/I4/FZEfZF4ExGubeD8LSuB1fRoJqcPMEZA7JK8hKKX3UYsK5stoRBklD2MF2XuJq RbmdRhWFG59EtICeUkHWiQU8B23W+KU7A49XSQ30CBx6bqXfL4KYQzDG+LF9fiSSFXwd W+ow== 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:x-spam-checked-in-group :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=3Be6U2q61MfVEI5XjsXNO9Cmk/JNUEcanYQ6K2MH2ak=; b=eq7di5h4ILVYrSKQZGZ7UbY2gJefc6PgaivskVhSy1aPVoVzFU7fxh1jGaQlPGwc+F 2Aa6Wv3yKpYyAbrAmuhyVl5h4xHpaj0eeCnORLEBQOVfkLo3hn6zN2QAboTcw2OQvSha LpEWIwStTQFQWXRv+5AQXwLpyUkJCJy2qCMTED6ntJZbDz46KgWC5/KXPbiL38kR8YuM K0rakEJfZGuRK0VCgQl0H5VFWn7A6BxvJ7PRJd7c6p+1qcJvh0108IMk97F3VLZIuz5o KprX+sOcud4+AWzcmA154lBaJzQqdhIpWkjUuYjjAxX9c14CQ+8nbd7+ZdEmifLbb07z o0zg== X-Gm-Message-State: ALoCoQlh6Nwuog7l1Rq2xvf+GRJ8srJFh/vDAmHV+IV4A52IPfBhCev85wdFY+Xp3Am8cl6G9Bg2 X-Received: by 10.182.225.230 with SMTP id rn6mr161786obc.20.1446624520627; Wed, 04 Nov 2015 00:08:40 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.152.98 with SMTP id ux2ls312784igb.39.gmail; Wed, 04 Nov 2015 00:08:39 -0800 (PST) X-Received: by 10.50.83.40 with SMTP id n8mr27727igy.1.1446624519675; Wed, 04 Nov 2015 00:08:39 -0800 (PST) In-Reply-To: X-Original-Sender: yannick.daveluy@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:22230 Archived-At: ------=_Part_6106_1051089625.1446624518488 Content-Type: multipart/alternative; boundary="----=_Part_6107_1195752805.1446624518489" ------=_Part_6107_1195752805.1446624518489 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable The direct application is nested inheritance. It's easier to illustrate it with an example: /* A generic interface File */ class IF { /* stubs interfaces */ struct a{}; struct b{}; .... struct z{}; }; /* a generic model built from interfaces */ *template class Model: * *BaseClasses...{* *struct a: * *BaseClasses::a...{};struct b* *: BaseClasses::b...{};...struct z* *: BaseClasses::z...{};};*}; /* Some user sp=C3=A9cific models */ class UserModelIF1 { /* only implement needed interfaces */ struct g { int i; float f;}; }; class UserModelIF2 { /* only implement needed interfaces */ struct t { int i; float f;}; }; class UserModel: public *Model { UserModel() { /* struct X would be a composition of all inherited interfaces */ }; }; Yannick=20 Le mardi 3 novembre 2015 10:45:42 UTC+1, yannick...@gmail.com a =C3=A9crit = : > > > When using variadic templates, the syntax does not allow to use virtual,= =20 > private, protected and public keywords prefixs for parameters. > > > e.g: > > > > > > > > > > > > > > > > > > > > > > > > > > > *template class A: BaseClasses...{ struct S:=20 > BaseClasses::S... {};};class B{ struct S{};};class C{ struct=20 > S{};};class D: public A< public virtual B, protected C > // =3D>do not=20 > compile{};=3D=3D> D should inherit from the following class A':class A': = public=20 > virtual B, protected C{ struct S: public virtual B::S, protected=20 > C::S{};};* > > Yannick > > --=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_6107_1195752805.1446624518489 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
The direct application is nested inheritance.

It= 9;s easier to illustrate it with an example:

/* A generic interface = File */
class IF
{
/* stubs interfaces */
struct a{};
struct= b{};
...
struct z{};
};

/* a generic model built from inte= rfaces */
template <class ... BaseClasses>
class Model: = BaseClasses...
{

struct a: BaseClasses= ::a...{};
struct b: BaseClasses::b...{};=
...
struct z: BaseClasses::z...{};};
= };

/* Some user sp=C3=A9cific models */
class UserModelIF1{
/* only implement needed interfaces */
struct g { int i; float f;}= ;
};
class UserModelIF2
{
/* only implement needed interfaces *= /
struct t { int i; float f;};
};

class UserModel: public M= odel<public virtual UserModelIF1, protected UserModelIF2>
{UserModel()
{
/* struct X would be a composition of all inherited in= terfaces */
};
};


Yannick
Le mardi 3 novembre 2015 10:= 45:42 UTC+1, yannick...@gmail.com a =C3=A9crit=C2=A0:

When using variadic templates,= =C2=A0 the syntax does not allow to use virtual, private, protected and pub= lic keywords prefixs for parameters.


e.g:

template <clas= s ... BaseClasses>
class A: BaseClasses...
{
=C2=A0=C2=A0=C2=A0= struct S: BaseClasses::S... {};
};

class B
{
=C2=A0=C2=A0= =C2=A0 struct S{};
};
class C
{
=C2=A0=C2=A0=C2=A0 struct S{};<= br>};


class D: public A< public virtual B, protected C > /= / =3D>do not compile
{
};

=3D=3D> D should inherit from = the following class A':
class A': public virtual B, protected C<= br>{
=C2=A0=C2=A0=C2=A0 struct S: public virtual B::S, protected C::S{};=
};

Yannick

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