220 6755 <47b487e0-390d-448e-818e-1f43ab4b0db9@isocpp.org> article Path: news.gmane.org!not-for-mail From: Mikhail Semenov Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Revision of N3702: Introducing an optional parameter for mem_fn. Date: Sun, 29 Sep 2013 00:36:38 -0700 (PDT) Lines: 147 Approved: news@gmane.org Message-ID: <47b487e0-390d-448e-818e-1f43ab4b0db9@isocpp.org> References: <0ffade3d-ac13-434c-b20a-85d611783fc1@isocpp.org> <2284c2d2-ec8e-43fb-90e7-c43ac9dc92c2@isocpp.org> <505813ae-956c-4693-b793-2ba47107c09c@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_1277_2243154.1380440198531" X-Trace: ger.gmane.org 1380440198 529 80.91.229.3 (29 Sep 2013 07:36:38 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 29 Sep 2013 07:36:38 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDC55PNFRYGRBCFRT6JAKGQE6J3RTKQ@isocpp.org Sun Sep 29 09:36:43 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ie0-f199.google.com ([209.85.223.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VQBYY-0004jX-AD for gclcip-std-proposals@m.gmane.org; Sun, 29 Sep 2013 09:36:42 +0200 Original-Received: by mail-ie0-f199.google.com with SMTP id e14sf15012663iej.10 for ; Sun, 29 Sep 2013 00:36:41 -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 :x-original-sender:reply-to:precedence:mailing-list:list-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=jNVqHhvDxbrdUIm4AMuX+fpZLYJT8ulcIXXFyEpQxLk=; b=o52pRR1149TGY3rdFHTd5Jj2m6tJW0IJ4nzwYybguW4UQ7HG9U/Ffq3gcLbyXjkoic iU1Hgg1+v6lTMawiXj7/OEdpRbg8rkg71i/8sw2qbOzonNg40YOxBK31BgHuTFiactV+ o5ZxERAHO7gmkJLOloVf0h1nBq1CflZHNshSod2VURwbAXcb2Sg3TOVD+ijih3rgKwwV OZZfAqTSUNLiUS8qx9wYDDm6INt6TUW+alkN1NP9QPTPG2k9S+sKkGDG8p24y+B//Zbx IRaztZbsDGFKZ2NGxoA3ZARINoQ7oaVWNArQMIeH0Otw6CiARB0P9IIkaOVLqIxNeeSm f6eA== X-Received: by 10.43.61.211 with SMTP id wx19mr10237238icb.17.1380440201285; Sun, 29 Sep 2013 00:36:41 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.1.68 with SMTP id 4ls1183564igk.22.canary; Sun, 29 Sep 2013 00:36:40 -0700 (PDT) X-Received: by 10.50.109.170 with SMTP id ht10mr325184igb.14.1380440200396; Sun, 29 Sep 2013 00:36:40 -0700 (PDT) In-Reply-To: X-Original-Sender: mikhailsemenov1957@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:6755 Archived-At: ------=_Part_1277_2243154.1380440198531 Content-Type: text/plain; charset=ISO-8859-1 It can be done even better: *#define memb_delegate(_a, _f)\* * [&(_a)](auto&& ... _args) { return (_a)._f(std::forward(_args)...);}* This can be used like this: *double r = integrate(member_delegate(a, fa), x1, x2, y1, y2, z1, z2, a1, a2, b1, b2);* (I haven't compiled it either). I works with various parameters. I have mentioned it a couple of times during discussions. By the way, I don't have access to twiki and failed to register. On Sunday, September 29, 2013 5:26:18 AM UTC+1, Jeffrey Yasskin wrote: > Thanks for the proposals. The Library Evolution group in Chicago > reviewed mem_fn and concluded that it's generally not worth extending > the callable wrappers, and that users should just use lambdas in > nearly all cases. C++14's generic lambdas with variadic captures make > this an even better tradeoff (note, I didn't compile this): > > double r = integrate > ([&a](const auto&... args) { return a.fa(args...);}, > x1, x2, y1, y2, z1, z2, a1, a2, b1, b2); > > http://wiki.edg.com/twiki/bin/view/Wg21chicago2013/N3702 > > On Thu, Sep 26, 2013 at 2:42 PM, Mikhail Semenov > > wrote: > > Revised proposal: support for a unique pointer and reference wrapper as > a > > second parameter is added, including a reference to a shared pointer. > The > > second parameter is move-constructible. > > > > > > -- > > > > --- > > 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-proposal...@isocpp.org . > > To post to this group, send email to std-pr...@isocpp.org . > > > Visit this group at > > http://groups.google.com/a/isocpp.org/group/std-proposals/. > -- --- 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_1277_2243154.1380440198531 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
It can be done even better:
#define= memb_delegate(_a, _f)\
  [&(_a)](auto&= amp;& ... _args) { return (_a)._f(std::forward<decltype(_args)>(_= args)...);}
 
This can be used like this= :
double r =3D integrate(member_delegate(a, fa),  x1= , x2, y1, y2, z1, z2, a1, a2, b1, b2);
 
= (I haven't compiled it either).
 
I works with var= ious parameters.
 
I have mentioned it a couple o= f times during discussions.
 
By the way, I don't = have access to twiki and failed to register.
 
&nb= sp;

On Sunday, September 29, 2013 5:26:18 AM UTC+1, Jeffrey Y= asskin wrote:
Thanks for the proposals. T= he Library Evolution group in Chicago
reviewed mem_fn and concluded that it's generally not worth extending
the callable wrappers, and that users should just use lambdas in
nearly all cases. C++14's generic lambdas with variadic captures make
this an even better tradeoff (note, I didn't compile this):

 double r =3D integrate
              ([&a](const auto&a= mp;... args) { return a.fa(args...);},
                 x1, x2, y= 1, y2, z1, z2, a1, a2, b1, b2);

http://wiki.edg.com/twiki/bin/view/Wg21chicago2013/N37= 02

On Thu, Sep 26, 2013 at 2:42 PM, Mikhail Semenov
<mikhailse...@gmail.com> wrote:
> Revised proposal: support for a unique pointer and reference wrapp= er as a
> second parameter is added, including a reference to a shared point= er. The
> second parameter is move-constructible.
>
>
> --
>
> ---
> 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-proposal...@isocpp.org.
> To post to this group, send email to std-pr...@isocpp.org.
> Visit this group at
> http://groups.google.com/a/isocpp.org/group/std= -proposals/.

--
 
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You received this message because you are subscribed to the Google Groups &= quot;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-proposals/<= /a>.
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