220 31939 <62e66de4-7c7a-4e1c-8343-b173b49cb594@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: hun.nemethpeter@gmail.com Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Improved variable declaration syntax Date: Mon, 3 Apr 2017 07:45:12 -0700 (PDT) Lines: 164 Approved: news@gmane.org Message-ID: <62e66de4-7c7a-4e1c-8343-b173b49cb594@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_1231_1084392551.1491230712839" X-Trace: blaine.gmane.org 1491230730 1858 195.159.176.226 (3 Apr 2017 14:45:30 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 3 Apr 2017 14:45:30 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBD3YT6VHQYIBB6N7RHDQKGQECFQOYBI@isocpp.org Mon Apr 03 16:45:26 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yb0-f199.google.com ([209.85.213.199]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cv3EC-000703-A3 for gclcip-std-proposals@m.gmane.org; Mon, 03 Apr 2017 16:45:08 +0200 Original-Received: by mail-yb0-f199.google.com with SMTP id c126sf12294581ybf.6 for ; Mon, 03 Apr 2017 07:45:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:message-id:subject:mime-version: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=nfR5CLTXsbkkUh5pSxPX0pvgTeI8t+vyaLQsovX5ZNs=; b=GiYtlq1xSpE4wrsIJeopK08TgcVSRudiO79z8j0CjeF3CoA2hafqYD5Zy3FgZOIt2E BcpMMcy1FcLIZAubLUmLhjnD633CnRGoZzN2isSwB33Xmach+qN9nqc0NKsF6ar4WJEO mQSs1KleaQOU0WyqzRkqEoD/ucpxsT0+uUtnD/yKZzcSVvv35Y1CPy79/1LJ1XIMl9sF 8vD20ouRmI9jW00rQEn7OKuMPBaGIY7DWyIC4O6dZmhNovJOQA6mR1AbsDHpaC33fvI6 xlQwWtJcPEspeX13EiUS/5iDO7Ybk89PRm2dCjTDpZL4T+Bo59YpdvNqeg0xBDfd3IVN JZNQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:message-id:subject:mime-version: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=nfR5CLTXsbkkUh5pSxPX0pvgTeI8t+vyaLQsovX5ZNs=; b=WTZsk884JoEyNW7Y1T8vhFGXxGDRflEvRehdvPlh72iPozVNMlN6AMVlzC37zTfXL3 udDXBCw2j68USaup+VvG3dj3Rbpmph6Dx5lmOI3CeYv7MGQy1VNeSYUIQzEYFmUbjimI eYO1PSxxqCMxWxbF4WoBu25ZMSdKhhQp+0Miws6ut0UmXqTIoSs8dBZVfLBkOBRitj1Y x7Y0GEBMg6hqNVPPEvDDCTHyWpvexagWmSC1qCtM+MMptDvEt/8h25AYZgC7Kpma+iYC DK7y5JP2XK2DQK6xjaa2w1lpv1VKlo70fdotTKRDiYJBv4O/tOlCmzvwDZbxte/lJX5X 3cFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:message-id:subject:mime-version :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=nfR5CLTXsbkkUh5pSxPX0pvgTeI8t+vyaLQsovX5ZNs=; b=MZg99oO/dvCOY8L/nvrZjUvoCEDOtj6zVqjxR82dYCD8SRs/iygaZYdJOVfm6T58ap B/hQY5pxHOyvvnGPbkqcf1hJKrYdTnLS+0GAINSESYySKoQb804qWDzMJmHIgdMKk3zU cmE3fY2Tj3BTVJfT5HnmlrqRrNUZlRpPY8cl9nyzcI6BAfBzik1XWkECjXddXABqMH2j n7YtzzXxMGKaP9UukkooUWJh8wZBSZilW30qiZh5l+X88dtNMb24kEkpEkVc8B7+x5cS iqDfoTz/qotEiZyqyq/BxhT6m3BqO/gE7Tbo53eoRhyML88jymfQpn5RflXjzfQbvyvS Wo+w== X-Gm-Message-State: AFeK/H3zpGQy8aqe/Yd0pS1hDRy2rxZGmm+JibNwZjHWf9BBtQ7rspgTKTm+sNP5nt1Xwg== X-Received: by 10.13.212.195 with SMTP id w186mr7846461ywd.105.1491230714110; Mon, 03 Apr 2017 07:45:14 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.27.155 with SMTP id z27ls1330919otd.14.gmail; Mon, 03 Apr 2017 07:45:13 -0700 (PDT) X-Received: by 10.157.25.203 with SMTP id k69mr713806otk.17.1491230713280; Mon, 03 Apr 2017 07:45:13 -0700 (PDT) X-Original-Sender: hun.nemethpeter@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:31939 Archived-At: ------=_Part_1231_1084392551.1491230712839 Content-Type: multipart/alternative; boundary="----=_Part_1232_1182156914.1491230712839" ------=_Part_1232_1182156914.1491230712839 Content-Type: text/plain; charset=UTF-8 Hi, I took part in so many syntax debates over the years on preferred variable declaration syntax. One of the neuralgic point of variable declaration syntax is the pointer and reference alignment style. The root problem is the following: int* a, b; This declares a pointer and an int which is confusing. So a common coding style to avoid this error is aligning pointer to variables: int *a, b; Which is also confusing sometimes as some type parts are separated from the "main" type. What I suggest is a new variable declaration syntax: // := , , ...; // so I can write int*:= a, b; // or int*:= a = nullptr, b = &a; // the following won't compile: int*:= *a, b; To avoid the type syntax confusion I also propose to deprecate old style variable declaration syntax as we can write tools to mechanically transform the code bases to this new syntax. I get this syntax from a previous thread: A more consistent variable declaration syntax by Andy Prowl https://groups.google.com/a/isocpp.org/forum/#!searchin/std-proposals/variable$20declaration/std-proposals/ITDME5hYiPw/l4HFz3jjik4J Peter -- 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. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/62e66de4-7c7a-4e1c-8343-b173b49cb594%40isocpp.org. ------=_Part_1232_1182156914.1491230712839 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Hi,


I took part in so ma= ny syntax debates over the years on preferred variable declaration syntax.<= /div>

One of the neuralgic point of variable declaration= syntax is the pointer and reference alignment style.

<= div>The root problem is the following:

int* a, b;

This declares a p= ointer and an int which is confusing. So a common coding style to avoid thi= s error is aligning pointer to variables:

int *a, b;

Which is also confusing somet= imes as some type parts are separated from the "main" type.
=

What I suggest is a new variable declaration syntax:

// <type>:=3D <identifier1>, <identifier2>, ..= ..;
// so I can wr= ite
int*:=3D a, b;

// or

int*:=3D= a =3D nullptr, b =3D &a;
// the f= ollowing won't compile:
int*:=3D = *a, b;

To = avoid the type syntax confusion I also propose to deprecate old style varia= ble declaration syntax as we can write tools to mechanically transform the = code bases to this new syntax.


I ge= t this syntax from a previous thread:=C2=A0

A more = consistent variable declaration syntax by Andy Prowl



Peter

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