220 21072 <37415448-4691-4d36-bd73-e4afac23cf4b@isocpp.org> article Path: news.gmane.org!not-for-mail From: Arthur O'Dwyer Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: auto return Date: Wed, 30 Sep 2015 15:56:07 -0700 (PDT) Lines: 136 Approved: news@gmane.org Message-ID: <37415448-4691-4d36-bd73-e4afac23cf4b@isocpp.org> References: <7deedcff-6776-4b3b-a3d1-3132f8ec1ae3@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_9720_640582435.1443653767270" X-Trace: ger.gmane.org 1443653775 6937 80.91.229.3 (30 Sep 2015 22:56:15 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 30 Sep 2015 22:56:15 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDLZJYWNDQIIRUNRWACRUBD2DKI34@isocpp.org Thu Oct 01 00:56:10 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pa0-f70.google.com ([209.85.220.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZhQIE-0007hG-Bn for gclcip-std-proposals@m.gmane.org; Thu, 01 Oct 2015 00:56:10 +0200 Original-Received: by pacex11 with SMTP id ex11sf94100562pac.2 for ; Wed, 30 Sep 2015 15:56:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to: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=TbAx+uPmXZ/Ff9mrutLKVYZdaE9oguXredBPDihePbE=; b=zFS824rRrPl+8kyDh1x+s0vZcYZI/52meTZqyJee1hVxcDCqHj0ZUHTenAH/ZUyKKX 6TA8GKQZ10O5Ayv9/0jVhFB4eg71AplD0n5I9o5O4X0+SbOhUextiYmrQBswsfo3+uem Fug60zDBi424MIEb+ERA0+HFBEhatRj7Jbd7PE905PmW+3VN5u41rrm0/p3oOust7keV J3wQhMxE3HGqYITlHlOGmaN0dZ1co02Gbsz793L0o9/0waCOcy51eKoFQYqo2aMdRO4C aWeIQeKCHUErMbSFOVB2wjDvGT2B1NNKb+jTJXKQDU4yjAAAg19wj9eTQnNh8AuMisDF dBDg== 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: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=TbAx+uPmXZ/Ff9mrutLKVYZdaE9oguXredBPDihePbE=; b=PzCujQYLCBNsvYpcpXQ9WjkKPcqD8V2GAtFfDsZHONVyJpeR2FRYycD9JnAPeVXq4S 9stLc0AM19I6CQudfZqEGnl6yOmR6ZH+ffssKAFe5gIXSSy2gbMltg7/Q92GKWLvgtoU 6tsT6s7aa4Zh/oSGFiC+ueasjLUV2A1X3PrzKmslDh4GDRg71NrpeN9m928PMJLaeBC8 28GjrRXvL35JOY6LmA9NGtTOOMZkRpnk3GaGkhKOrZeP3CPbfRx1TkQaGln/1KBG4DfC L2F5GaqC+Qqq00nIaxBuh4vhLpS1w/2VphrfYinsgR2Ib5I1pkHB8HNY6h/UGYj2z65a pLdg== X-Gm-Message-State: ALoCoQn+/2QRZBIWLCdM6P8vAQShUlK675sozVsGNStYFrJpyPVvUnaj9Bjg7yibcymdbyimOQ1S X-Received: by 10.68.206.106 with SMTP id ln10mr5429935pbc.5.1443653769148; Wed, 30 Sep 2015 15:56:09 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.61.100 with SMTP id o4ls37755igr.26.canary; Wed, 30 Sep 2015 15:56:08 -0700 (PDT) X-Received: by 10.50.110.74 with SMTP id hy10mr253788igb.1.1443653768296; Wed, 30 Sep 2015 15:56:08 -0700 (PDT) In-Reply-To: X-Original-Sender: arthur.j.odwyer@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:21072 Archived-At: ------=_Part_9720_640582435.1443653767270 Content-Type: multipart/alternative; boundary="----=_Part_9721_545280241.1443653767271" ------=_Part_9721_545280241.1443653767271 Content-Type: text/plain; charset=UTF-8 Turning "return" into a primary-expression is a non-starter. int foo() { return+1; } int bar() { return(1); } and probably some really crazy arbitrary-lookahead-requiring things with lambda syntax: is return[a=1] an array indexing expression or a return statement returning a lambda? So we can forget about that syntax and go back to the whiteboard... which means re-confronting the question of "what problem is it that we're really trying to solve, again?" Is it that our shortest functions aren't short enough? Is it that we don't feel in control enough of RVO and want to annotate the "return-slot variable" for our own peace of mind? ...What's the problem being solved? On Wednesday, September 30, 2015 at 12:41:14 PM UTC-7, Tony V E wrote: > > > > On Wed, Sep 30, 2015 at 3:30 PM, Matthew Woehlke > wrote: > >> >> I've written ' result; ... return result;' often enough that I >> wouldn't mind a shortcut. I'd be potentially interested in this much of >> the proposal: >> >> auto foo(...) // arguments not important >> { >> while (...) >> return.emplace_back(...); >> return; >> } >> >> That is, one can use 'return' as a local variable; > > > In that case, I'd expect that last line to be > > return return; > > And (sadly?) I think I'd be more comfortable with that. > > Tony > > -- --- 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/. ------=_Part_9721_545280241.1443653767271 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Turning "return" into a primary-expression = is a non-starter.

=C2=A0 =C2=A0 int foo() {
<= div>=C2=A0 =C2=A0 =C2=A0 =C2=A0 return+1;
=C2=A0 =C2=A0 }

=C2=A0 =C2=A0 int bar() {
=C2=A0 =C2=A0 =C2=A0 = =C2=A0 return(1);
=C2=A0 =C2=A0 }

and pr= obably some really crazy arbitrary-lookahead-requiring things with lambda s= yntax: is return[a=3D1] an array indexing expression or a return statement = returning a lambda?

So we can forget about that sy= ntax and go back to the whiteboard... which means re-confronting the questi= on of "what problem is it that we're really trying to solve, again= ?" =C2=A0Is it that our shortest functions aren't short enough? = =C2=A0Is it that we don't feel in control enough of RVO and want to ann= otate the "return-slot variable" for our own peace of mind? =C2= =A0...What's the problem being solved?


On Wedne= sday, September 30, 2015 at 12:41:14 PM UTC-7, Tony V E wrote:


On Wed, Sep 30, 2015 at 3:30 PM, Matthew Woehlke <mwoehlk...@gmail.com> wrote:

I've written '<decl> result; ... return result;' o= ften enough that I
wouldn't mind a shortcut. I'd be potentially interested in this muc= h of
the proposal:

=C2=A0 auto foo(...) // arguments not important
=C2=A0 {
=C2=A0 =C2=A0 while (...)
=C2=A0 =C2=A0 =C2=A0 return.emplace_back(...);
=C2=A0 =C2=A0 return;
=C2=A0 }

That is, one can use 'return' as a local variable;

In that case, I'd expect that last line to be

=C2=A0=C2=A0=C2=A0 return return;

And (sadly?) I= think I'd be more comfortable with that.

Tony

--

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