220 4625 <35af8d3d-8ed6-441c-94d0-b898711190b1@isocpp.org> article Path: news.gmane.org!not-for-mail From: potswa@gmail.com Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Changing lambda scope Date: Mon, 27 May 2013 05:18:42 -0700 (PDT) Lines: 161 Approved: news@gmane.org Message-ID: <35af8d3d-8ed6-441c-94d0-b898711190b1@isocpp.org> References: <01190eaa-6223-4d3c-a9d3-b0d850aab98e@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_552_13112465.1369657122286" X-Trace: ger.gmane.org 1369657125 23634 80.91.229.3 (27 May 2013 12:18:45 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 27 May 2013 12:18:45 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCW25A7E3QCRBI46RWGQKGQEZGTOC4Q@isocpp.org Mon May 27 14:18:46 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oa0-f69.google.com ([209.85.219.69]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1UgwNx-0007V8-3h for gclcip-std-proposals@m.gmane.org; Mon, 27 May 2013 14:18:45 +0200 Original-Received: by mail-oa0-f69.google.com with SMTP id i10sf36099215oag.8 for ; Mon, 27 May 2013 05:18:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-beenthere: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=J5idllGDJ00P+yynfFqbhKLKb7p2Wc8gnFCtO3aoZ5A=; b=PfuPEOl0BOvZte+F4wDZhwkQaHJXFTORrXEuqX2ve8xkVcGw/ZULYngiJMJN48q6L5 Szifl/Cc7TT0NLR9vtx6PusAHAlY9fgDdgUS21dDGtboD0pZ9uDp5m3fdzq1PQjzwyO8 yYgAK4CeqIILntom5hVPTxZt8265yCZU431IPxDXV+bpSBZp7KfuIEdLwNRuaTzFwJA2 De8LUyzwTNg8ivrzTPnxY9GslKz+rkz4sZvKn5se3sqE0kqjrDH3IACgcGH4b7bRBkPU 51hpiG2y9hJtypgBhGSzYnhJJsBkzoCXDMSNfMNszdchXXEN/G1U4FfEpUoHd5xQWAO7 CCCA== X-Received: by 10.50.112.163 with SMTP id ir3mr8742453igb.4.1369657124087; Mon, 27 May 2013 05:18:44 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.62.8 with SMTP id u8ls1979009igr.16.canary; Mon, 27 May 2013 05:18:43 -0700 (PDT) X-Received: by 10.50.12.38 with SMTP id v6mr949385igb.4.1369657123326; Mon, 27 May 2013 05:18:43 -0700 (PDT) In-Reply-To: X-Original-Sender: potswa@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:4625 Archived-At: ------=_Part_552_13112465.1369657122286 Content-Type: text/plain; charset=ISO-8859-1 > You can return a lambda or a local class from a lambda in C++11, so that > doesn't count as an excuse for noticing this now because > we can return local types from a non-lambda in C++14. > Sort of. You can return it from a lambda but you can't return it out of the enclosing non-lambda function scope. The only way to pass it out of the * namespace*, which is what matters, is to pass it into a template, which is what I did with my example. By the way, the language as-is seems deeply flawed. Only a singly-nested class has an associated namespace; nest a class inside a nested class and it becomes disconnected from its namespace. - If T is a class type (including unions), its associated classes are: the class itself; the class of which it is a member, if any; and its direct and indirect base classes. Its associated namespaces are the namespaces of which its associated classes are members. GCC and Clang both incorrectly accept this example: namespace n { struct s { struct n1 { struct n2 {}; }; }; int f( s::n1::n2 ) { return 3; } } int i = f( n::s::n1::n2() ); -- --- 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 email 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-proposals/?hl=en. ------=_Part_552_13112465.1369657122286 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
You can return a lambda or a local class from a= lambda in C++11, so that doesn't count as an excuse for noticing this now = because
we can return local types from a non-lambda in C++14.
<= /div>

Sort of. You can return it from a la= mbda but you can't return it out of the enclosing non-lambda function scope= .. The only way to pass it out of the namespace, which is what matter= s, is to pass it into a template, which is what I did with my example.
<= br>By the way, the language as-is seems deeply flawed. Only a singly-nested= class has an associated namespace; nest a class inside a nested class and = it becomes disconnected from its namespace.

=09 =09 =09 =09 =09

  • = If T= is= a class type (including unions), its associated classes are: the class its= elf; the class of which it is a member, if any; and its direct and indirect base classes. Its associated na= mespaces are the namespaces of which its associated classes are members.

=09
GCC and Clang both incorrectly accept this example:

namespace n {
struct s { struct = n1 { struct n2 {}; }; };=
int f( s::n1::n2 )= {<= span style=3D"color: #000;" class=3D"styled-by-prettify"> return 3; }<= br>}
int i =3D f( n::= s::= n1::n2() );

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