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[213.162.250.23]) by mx.google.com with ESMTPS id v10-v6si2435610ljj.391.2018.08.23.10.17.02 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 23 Aug 2018 10:17:02 -0700 (PDT) Received-SPF: pass (google.com: domain of david@westcontrol.com designates 213.162.250.23 as permitted sender) client-ip=213.162.250.23; Original-Received: from localhost (localhost [127.0.0.1]) by mailfilter04.hatteland.com (Postfix) with ESMTP id F2E91102C4D; Thu, 23 Aug 2018 19:17:01 +0200 (CEST) X-Virus-Scanned: by SpamTitan at hatteland.com Original-Received: from mailfilter04.hatteland.com (localhost [127.0.0.1]) by mailfilter04.hatteland.com (Postfix) with ESMTP id 53545102C3A; Thu, 23 Aug 2018 19:17:01 +0200 (CEST) Original-Received: from JHSVMHUB02.netsentral.no (unknown [172.21.1.26]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mailfilter04.hatteland.com (Postfix) with ESMTPS id 50ECC102C1D; Thu, 23 Aug 2018 19:17:01 +0200 (CEST) Original-Received: from [192.168.4.245] (172.21.20.100) by e2010.hatteland.com (172.21.1.26) with Microsoft SMTP Server (TLS) id 14.3.224.2; Thu, 23 Aug 2018 19:17:02 +0200 In-Reply-To: Content-Language: en-GB X-Originating-IP: [172.21.20.100] X-Original-Sender: david@westcontrol.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of david@westcontrol.com designates 213.162.250.23 as permitted sender) smtp.mailfrom=david@westcontrol.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:39987 Archived-At: On 23/08/18 18:44, Matthew Woehlke wrote: > On 2018-08-19 07:23, David Brown wrote: >> here I am talking about the optional use of parameter names to improve >> readability, help write correct code, help spot incorrect code, and - >> optionally - to allow re-arranging of parameter order and skipping >> defaults using names. >=20 > If we *don't* get the optional parts (skipping, reordering)... then > what's the point? >=20 > If we don't get the optional parts, you might as well modify your > compiler to warn you about: >=20 > void foo(int x); > foo(/*y=3D*/5); // warning: 'y' !=3D 'x' >=20 > ...and no language change is required. I see two disadvantages of that. One is that it is seriously ugly=20 having comments in the middle of a function call - "foo(.y =3D 5)" is very= =20 much nicer and neater syntax. The other is that because there is no=20 standard, and neither limits nor requirements in what you might have in=20 these comments (maybe someone wants to write "foo( /* was 4 in last=20 version */ 5);", it would be hard to get it in common use. But as far as I see it, it is this checking that is the most important=20 feature. It covers the two most vital points - it aids readability and=20 clarity of the code, and it means mistakes are more likely to be caught=20 at compile-time. These are both /good/ things - and IMHO they are worth=20 allowing the syntax "foo(.y =3D 5);" even if you don't get anything else. (I'd like to see that same syntax in C as well, including calling C=20 functions from C++ - and I think re-ordering and overloading would not=20 be a consideration for C.) >=20 >> There are two other use-cases where there could be debate about the best >> solution: >> >> If the call has the right parameter names, but the wrong order, should >> that be a warning, or error, or should the compiler "magically" correct >> the order?=C2=A0 If strong naming is used, the compiler should certainly= be >> able to re-order the parameters without giving any complaints. >=20 > Honestly, this is a good question. There are arguments on both sides > whether or not to allow reordering, and I am somewhat avoiding taking a > stance. >=20 I have some rough preferences here - but I freely admit that I don't=20 have the experience at guessing what the complications might be, and I=20 leave it to the experts to see if the stance is forced by issues that I=20 have not thought about. > That said, FWIW I think I'm less okay with reordering weak names than > strong names. >=20 >> The other case is for skipping arguments.=C2=A0 Again, with strong namin= g >> this should be supported.=C2=A0 I believe it /could/ be supported fine w= ith >> weak naming, but would again be okay with the safer solution of not >> allowing it without strong naming. >=20 > Agreed. (Skipping is sort of a "weak" form of reordering.) >=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. To view this discussion on the web visit https://groups.google.com/a/isocpp= ..org/d/msgid/std-proposals/35f836e7-f7af-e36f-e5f4-2be447d65576%40westcontr= ol.com. .