220 7148 article Path: news.gmane.org!not-for-mail From: Brendon Costa Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Named arguments proposal Date: Wed, 9 Oct 2013 06:15:21 +1100 Lines: 132 Approved: news@gmane.org Message-ID: References: <74166da9-20f4-49b0-a9e6-47bf5be92e35@isocpp.org> <6ba6b273-76df-4037-9851-4a2ab98f0b68@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=001a1133e3300577ca04e83f9779 X-Trace: ger.gmane.org 1381259720 8978 80.91.229.3 (8 Oct 2013 19:15:20 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 8 Oct 2013 19:15:20 +0000 (UTC) To: "std-proposals@isocpp.org" Original-X-From: std-proposals+bncBC573SMG3INBBSVT2GJAKGQEVDLWU3Y@isocpp.org Tue Oct 08 21:15:24 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wg0-f71.google.com ([74.125.82.71]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VTcke-0002Ux-D2 for gclcip-std-proposals@m.gmane.org; Tue, 08 Oct 2013 21:15:24 +0200 Original-Received: by mail-wg0-f71.google.com with SMTP id l18sf12030056wgh.6 for ; Tue, 08 Oct 2013 12:15:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :x-original-sender:x-original-authentication-results:reply-to :precedence:mailing-list:list-id:list-post:list-help:list-archive :list-subscribe:list-unsubscribe:content-type; bh=YXYCyV+uJNAVvEGWJlTUt+BGIu1TZ28Bh9ksaE7dZRo=; b=he2kQfLIBuCoLD3f3uRO+YtnnMw/fxjwoxyYBtb6S5Gr7S49yllbSX+JmVBj3PFThH UGcstltBXga03okikf34b4I+5jwEf3Cr17d6JSkou2/DZtmHz5MHpsNrOm644IVsvnLa FXDyrwSZgd0j8oz4dXBBAzET8BbHrlVWG9sV3UwyUuSFahQnpFYLZzxtlKpoden8ycjr 0L5W7K+8IsDR6IJHzL7qBoGlDDjMvYxkDD2XP52OwEM0q5QPfX0Etnjaw2gO9RCJS5YA Nt5LzASmYqJXi5QMiBiBRpROcZXAz5/qXFbIb/2ATrIpfrHK0uTL6LUe4coxvtsVVKtt Mj5Q== X-Received: by 10.180.80.229 with SMTP id u5mr1256625wix.6.1381259723757; Tue, 08 Oct 2013 12:15:23 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.180.218.130 with SMTP id pg2ls1286606wic.41.canary; Tue, 08 Oct 2013 12:15:21 -0700 (PDT) X-Received: by 10.205.65.78 with SMTP id xl14mr3117696bkb.1.1381259721590; Tue, 08 Oct 2013 12:15:21 -0700 (PDT) Original-Received: from mail-lb0-x229.google.com (mail-lb0-x229.google.com [2a00:1450:4010:c04::229]) by mx.google.com with ESMTPS id i5si5464040bkr.182.1969.12.31.16.00.00 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 08 Oct 2013 12:15:21 -0700 (PDT) Received-SPF: pass (google.com: domain of brendon.j.costa@gmail.com designates 2a00:1450:4010:c04::229 as permitted sender) client-ip=2a00:1450:4010:c04::229; Original-Received: by mail-lb0-f169.google.com with SMTP id z5so7261302lbh.14 for ; Tue, 08 Oct 2013 12:15:21 -0700 (PDT) X-Received: by 10.112.55.173 with SMTP id t13mr2747858lbp.39.1381259721142; Tue, 08 Oct 2013 12:15:21 -0700 (PDT) Original-Received: by 10.114.98.100 with HTTP; Tue, 8 Oct 2013 12:15:21 -0700 (PDT) In-Reply-To: X-Original-Sender: brendon.j.costa@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of brendon.j.costa@gmail.com designates 2a00:1450:4010:c04::229 as permitted sender) smtp.mail=brendon.j.costa@gmail.com; dkim=pass header.i=@gmail.com; dmarc=pass (p=NONE dis=NONE) header.from=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:7148 Archived-At: --001a1133e3300577ca04e83f9779 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 9 October 2013 00:14, Diego S=E1nchez wrote: > Skipping over optional argument I don't see the reason for the restrictions or the declaration markup. What we are saying is that we can only call functions that are marked up in the declaration with keyword arguments? I.e. Named arg calls cant be applied to existing functions. Why do we need to decorate the declaration at all? Why cant we have: void f(int x, int y=3D0, int z=3D0); and be able to call it like: f(x:3, z:12); f(z:12, x:3); // Order does not matter for named params f(1,2,3); f(1, z:0); f(2, x:12); // Compile error If the reason is that existing declarations can already have multiple different arg names, then that could easily become a compile error when attempting to use named arg calls with those functions. All other functions written in a sensible way could be called using the named arg syntax. You can thus use legacy code, or code written in C etc. This would not change anything about a function declaration or ABI or API in a non-backwards compatible way. It only adds extra ways to be used at the call site. Surely this can be resolved easily: * First resolve non-named args (holes not allowed, must come before named args) * Second resolve named args * Resolve any defaults * If any args in the function call don't have a value then it is a compile error --=20 ---=20 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 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-proposa= ls/. --001a1133e3300577ca04e83f9779 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable

= On 9 October 2013 00:14, Diego S=E1nchez <dsde71@gmail.com> w= rote:
Skipping over optional argument

I don't see the r= eason for the restrictions or the declaration markup. What we are saying is= that we can only call functions that are marked up in the declaration with= keyword arguments? I.e. Named arg calls cant be applied to existing functi= ons.

Why do we n= eed to decorate the declaration at all?
Why cant we have:
void f(int x, i= nt y=3D0, int z=3D0);

and be able to = call it like:
f(x:3, z:12);
f(z:12,=A0x:3); // Order does n= ot matter for named params
f(1,2,3);
f(1, z:0);

f(2, x:12); // Compile error

If the reason is that existing declara= tions can already have multiple different arg names, then that could easily= become a compile error when attempting to use named arg calls with those f= unctions. All other functions written in a sensible way could be called usi= ng the named arg syntax. You can thus use legacy code, or code written in C= etc.

This would = not change anything about a function declaration or ABI or API in a non-bac= kwards compatible way. It only adds extra ways to be used at the call site.=

Surely this= can be resolved easily:
* First resolve no= n-named args (holes not allowed, must come before named args)
* Second resolve named args
* Resolve any d= efaults
* If any args in the function call = don't have a value then it is a compile error


<= br>

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