220 1505 article Path: news.gmane.org!not-for-mail From: Arthur Tchaikovsky Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: making using declaration more precise Date: Tue, 8 Jan 2013 00:54:25 -0800 (PST) Lines: 108 Approved: news@gmane.org Message-ID: References: <738f626c-3b23-4c74-9eea-2c2246921a81@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_791_17842400.1357635265371" X-Trace: ger.gmane.org 1357635265 22387 80.91.229.3 (8 Jan 2013 08:54:25 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 8 Jan 2013 08:54:25 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDL6FI4NYYERBQV5V6DQKGQE5PBAMBY@isocpp.org Tue Jan 08 09:54:42 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ye0-f197.google.com ([209.85.213.197]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1TsUxG-0000Bp-AV for gclcip-std-proposals@m.gmane.org; Tue, 08 Jan 2013 09:54:42 +0100 Original-Received: by mail-ye0-f197.google.com with SMTP id q9sf318171yen.4 for ; Tue, 08 Jan 2013 00:54:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:x-beenthere:x-received:date:from:to:message-id :in-reply-to:references:subject:mime-version:x-original-sender :reply-to:precedence:mailing-list:list-id:x-google-group-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=WdmQGAFxS+BXxQO0R2AZ5ZKAIp9v/FWI+wXa6l0laCA=; b=EpHYhuiUCmoBD5n1DJJ8jqgzksTCBAw8m9Ms7Fj1dRAbxR5ltRkS2zttZXbwojTS6l MjGVIJJ7Mxl43W5LSUAny+Svtrj5JmiK76u0H8AyRf7n+xrBujehoz/pLvIH4z1BLVvD tEKmZEt1nXCiYaveViy8845d7vk0UirL6xnLEuILfiKLzKtGUyf6QbpKdqZH6LRpPiLG KeoiMO5MRFLMicb/5cZDkRnhornMYvy32e3Yj7+g6QfONXmNFjX/KWuKZfQnPRF8YyVJ 363iyRny8liR7ss20NjJBSc0m7OM1l/dWhrpmyoJRI+j2B41ejV9J7t3GE0quYLViUz2 k5Hg== X-Received: by 10.224.178.204 with SMTP id bn12mr7199783qab.1.1357635266193; Tue, 08 Jan 2013 00:54:26 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.49.116.139 with SMTP id jw11ls171938qeb.37.gmail; Tue, 08 Jan 2013 00:54:25 -0800 (PST) X-Received: by 10.49.15.100 with SMTP id w4mr11089809qec.26.1357635265773; Tue, 08 Jan 2013 00:54:25 -0800 (PST) In-Reply-To: <738f626c-3b23-4c74-9eea-2c2246921a81@isocpp.org> X-Original-Sender: atch.cpp@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:1505 Archived-At: ------=_Part_791_17842400.1357635265371 Content-Type: text/plain; charset=ISO-8859-1 >Thinking like this is what makes me want the C++ committee to establish some >kind of "small feature" group. I believe that this would work really great and C++ could only benefit from it. On Saturday, 5 January 2013 18:07:03 UTC, Arthur Tchaikovsky wrote: > > I wonder if anyone feels the same as me about using declaration while > specifying members from base class? As things are now, it is very blunt and > not very precise tool, which could be quite easily tweaked. > What I mean is: > > class A > { > public: > void f(); > void f(int); > }; > > class B: public A > { > using A::f;//here we cannot make a choice on which one we would like to > use in our B class, which sometimes is ok... > }; > > but in scenario: > class A > { > void f(int); > public: > void f(); > }; > > class B :public A > { > using A::f;//will not compile even though the only fnc we want is A::f() > }; > > What I would like to propose is following backwards compatible syntax: > > class B :public A > { > using A::f;//here I'm specifying that I want use every fnc 'f' from A - > just like before, but this will not compile > using A::f();//here I explicitly specify which fnc I want to use > }; > > The use case which is I believe compelling is the one that if function f > overloaded and one or more is declared private, this actively prohibits us > from the use of any other, non-private functions 'f' from the base class. > > Looking forward to comments. > > -- ------=_Part_791_17842400.1357635265371 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable >Thinking like this is what makes= me want the C++ committee to establish some 
>kind of "smal= l feature" group.

I belie= ve that this would work really great and C++ could only benefit from it.

On Saturday, 5 January 2013 18:07:03 UTC, Arthur Tchaiko= vsky wrote:
I wonder if anyone= feels the same as me about using declaration while specifying members from= base class? As things are now, it is very blunt and not very precise tool,= which could be quite easily tweaked.
What I mean is:

class A
{
public:
void f();
void f(int);
};

class B: public A
{
using A::f;//here we cannot make a choice on which one= we would like to use in our B class, which sometimes is ok...
};=

but in scenario:
class A
{
void f(int);
public:
void f();
};

class B :public A
{
using A::f;//= will not compile even though the only fnc we want is A::f()
};

What I would like to propose is following backwards = compatible syntax:

class B :public A
{
using A::f;//here I'm specifying that I want use every fnc 'f= ' from A - just like before, but this will not compile
using A::f= ();//here I explicitly specify which fnc I want to use
};

The use case which is I believe compelling is = the one that if function f overloaded and one or more is declared &nbs= p;private, this actively prohibits us from the use of any other, non-privat= e functions 'f' from the base class.

Looking forwa= rd to comments.

--
 
 
 
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