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Botet Escriba" Newsgroups: gmane.comp.lang.c++.isocpp.general,gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: [c++std-core-27227] Re: An implementation of enhanced auto deduction and abbreviated template syntax using Clang Date: Sat, 07 Mar 2015 17:51:07 +0100 Lines: 259 Approved: news@gmane.org Message-ID: <54FB2C7B.3080009@wanadoo.fr> References: <465969eb-2f8b-41bb-91af-d8a9e22985e7@isocpp.org>,<54F9ED4C.2030108@stroustrup.com> <20150306185818.6508625.910.1394@blackberry.com> Reply-To: std-discussion@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="------------010009050209080206050501" X-Trace: ger.gmane.org 1425747080 14947 80.91.229.3 (7 Mar 2015 16:51:20 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 7 Mar 2015 16:51:20 +0000 (UTC) Cc: "std-proposals@isocpp.org" , "faisalv@gmail.com" , "hsutter@microsoft.com" To: std-discussion@isocpp.org, Bjarne Stroustrup Original-X-From: std-discussion+bncBDH67CONY4PBB7OY5STQKGQES24UVQY@isocpp.org Sat Mar 07 17:51:10 2015 Return-path: Envelope-to: gclcig-std-discussion@m.gmane.org Original-Received: from mail-lb0-f199.google.com ([209.85.217.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1YUHwU-0004Ms-99 for gclcig-std-discussion@m.gmane.org; Sat, 07 Mar 2015 17:51:10 +0100 Original-Received: by lbvn10 with SMTP id n10sf7116154lbv.1 for ; Sat, 07 Mar 2015 08:51:09 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:message-id:date:from:user-agent:mime-version:to :cc:subject:references:in-reply-to:content-type:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe; bh=gkna4X3bXLcKSh3lOVTk9NhVfX0W10x9hlEo1KcRYwc=; b=IuyhdEDIFFGN5uoUTz9deBXhxY1qJCSUk5ELCfcZjYggiZFyzC7F7aAdCgzsePFr1x sE136PrZ6pPRtoXQKdy5LJFBxnTSp063w7I4yS/OLlYi5KqS7ts4+RMULA9GohJ3rurY xuvZHt2sj4IeZAO0JeSjXsNo1hpO5Qt3Qxd8Zb+QRVxhuJoRQtABwINaCIecolOwHzXV jbjx/ntnICLdoDWmVYJulg/E1h4GCMijEkujUrM/dQlEHKNh/v78Fg9s4L44KIkxWK9F 2+iO8DsyGAVEJudbod0Ih3bk+rgg79K1AIeSDoJax+FSqNy+a4oJxERVPzkswF4bWrmT A0Mw== X-Gm-Message-State: ALoCoQnkhI3JYFjmRaCwURxbVNi713/iSKRXgpbp12uipQA9dBhX9hu62R2q1SVxLpKfawQv/JAO X-Received: by 10.180.182.201 with SMTP id eg9mr3477995wic.3.1425747069818; Sat, 07 Mar 2015 08:51:09 -0800 (PST) X-BeenThere: std-discussion@isocpp.org Original-Received: by 10.180.103.71 with SMTP id fu7ls281214wib.29.canary; Sat, 07 Mar 2015 08:51:08 -0800 (PST) X-Received: by 10.195.12.167 with SMTP id er7mr41992687wjd.54.1425747068868; Sat, 07 Mar 2015 08:51:08 -0800 (PST) Original-Received: from smtp.smtpout.orange.fr (smtp05.smtpout.orange.fr. [80.12.242.127]) by mx.google.com with ESMTP id e3si25619736wjs.203.2015.03.07.08.51.08 for ; Sat, 07 Mar 2015 08:51:08 -0800 (PST) Received-SPF: none (google.com: vicente.botet@wanadoo.fr does not designate permitted sender hosts) client-ip=80.12.242.127; Original-Received: from iMac-de-Vicente-Botet-Escriba.local ([2.11.66.123]) by mwinf5d09 with ME id 0gr51q00P2fZjpN03gr6FD; Sat, 07 Mar 2015 17:51:08 +0100 X-ME-Helo: iMac-de-Vicente-Botet-Escriba.local X-ME-Auth: dmljZW50ZS5ib3RldEB3YW5hZG9vLmZy X-ME-Date: Sat, 07 Mar 2015 17:51:08 +0100 X-ME-IP: 2.11.66.123 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 In-Reply-To: <20150306185818.6508625.910.1394@blackberry.com> X-Original-Sender: vicente.botet@wanadoo.fr X-Original-Authentication-Results: mx.google.com; spf=none (google.com: vicente.botet@wanadoo.fr does not designate permitted sender hosts) smtp.mail=vicente.botet@wanadoo.fr Precedence: list Mailing-list: list std-discussion@isocpp.org; contact std-discussion+owners@isocpp.org List-ID: X-Google-Group-Id: 495566654649 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.general:5053 gmane.comp.lang.c++.isocpp.proposals:16845 Archived-At: This is a multi-part message in MIME format. --------------010009050209080206050501 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Le 06/03/15 19:58, Tony Van Eerd a =C3=A9crit : > If all we need is auto, then is the next step: > > struct X > { > int x; > auto y; > }; > > X is obviously a template? > So is Y: > > struct Y > { > int x; > ForwardIterator y; > }; > > =E2=80=8E? > > (Again, I'm not actually against 'auto means template function'=E2=80=8E;= I=20 > just bring up counter arguments to be comfortable that we explored the=20 > design space and that we have a path of consistency going forward) > > While for template functions the type is deduced, how could you deduce=20 the type for auto or ForwardIterator. How would you declare an instance=20 of X, or a parameter of type X. X v; what if we had struct X { auto x; auto y; }; X v; Should the parameters need to be given in the order of declaration of=20 the auto/Concept data members? I find this confusing. Vicente --=20 ---=20 You received this message because you are subscribed to the Google Groups "= ISO C++ Standard - Discussion" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-discussion+unsubscribe@isocpp.org. To post to this group, send email to std-discussion@isocpp.org. Visit this group at http://groups.google.com/a/isocpp.org/group/std-discuss= ion/. --------------010009050209080206050501 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Le 06/03/15 19:58, Tony Van Eerd a =C3=A9crit=C2=A0:
If all we need is auto, then is the next step:

struct X
{
=C2=A0 =C2=A0 int x;
=C2=A0 =C2=A0 auto y;
};

X is obviously a template?
So is Y:

struct Y
{
=C2=A0 =C2=A0 int x;
=C2=A0 =C2=A0 ForwardIterator y;
};

=E2=80=8E?

(Again, I'm not actually against 'auto means template function'=E2=80=8E; I just bring up counter arguments to be comfort= able that we explored the design space and that we have a path of consistency going forward)=C2=A0


While for template functions the type is deduced, how could you deduce the type for auto or ForwardIterator. How would you declare an instance of X, or a parameter of type X.

X<???> v;

what if we had

struct X
{
=C2=A0 =C2=A0 auto x;
=C2=A0 =C2=A0 auto y;
};

X<???, ???> v;

Should the parameters need to be given in the order of declaration of the auto/Concept data members?

I find this confusing.

Vicente

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