220 31894 <00f80877-4564-406b-9dc5-d2d961b8dce3@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: Raffaele Rossi Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: This variable should not be named: an identifier (not) to remember Date: Thu, 30 Mar 2017 01:12:46 -0700 (PDT) Lines: 113 Approved: news@gmane.org Message-ID: <00f80877-4564-406b-9dc5-d2d961b8dce3@isocpp.org> References: <985b9b2a-c734-45eb-95f4-db4dc0d309a1@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_3045_308760219.1490861566356" X-Trace: blaine.gmane.org 1490861584 24465 195.159.176.226 (30 Mar 2017 08:13:04 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 30 Mar 2017 08:13:04 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBC6IBYFLW4MRB7736LDAKGQEMEDOFKQ@isocpp.org Thu Mar 30 10:12:59 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oi0-f69.google.com ([209.85.218.69]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ctVCE-0004Gh-31 for gclcip-std-proposals@m.gmane.org; Thu, 30 Mar 2017 10:12:42 +0200 Original-Received: by mail-oi0-f69.google.com with SMTP id r203sf18257907oib.15 for ; Thu, 30 Mar 2017 01:12:48 -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:in-reply-to:references: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=SrhgL6ErhD2VJJjnF4ALmSjok7mqYoJNu28PMrD6Dvk=; b=RoIJB+MvViPele+Gzu+BzU4HRGmNjxO6RH+YPNhGbXg6dHtKepwo4AhI0njF2/aW7w f09Lly1axCUZ9b7CLjYZHEh23MhLSHd407hjDSycHfhHWZZps/itA9sV1FlBEI/Dwk7A esF917UmnJSSAcZ2XGHxjNjQq8PKDcKUgwMHHXVksAfNAW30ENg0lKIop809kQaG7gxu DRNaSv7G89xz3hoFelpL7Es5tfnpKB6DoeVSMc9Aa7p7dq4jrKDMnkaK/JZtrIqoSFhg IcL2c8AWDl1Qekoj3GrDJORqzrLJeUBBugsGLZzOfdgfC8nNDyA6CEedAvBmXEiE3A+0 pWig== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:message-id:in-reply-to:references: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=SrhgL6ErhD2VJJjnF4ALmSjok7mqYoJNu28PMrD6Dvk=; b=Vu3Pmh79fvnXt49Zq3pImy3izRkS2w3nBNlxdMZzRIgP3X/KWSUoZkyet67dsuYAZ7 23VmJeoMLZgS5WBWu75ZEMZyFz/P3IztNWV/1OMsbX7KMFJkU7ouiM9adZ1gyTtdm12u 0hIT79sd9begbU/Ay9W0AcmtB17CHD5Kx1PMY5sxml+SUvOLrK+wjgEd7OYKzezaUh8z 4xj1SVqfhGNIcXzh174mIWLCDT9N6i8wCuDWsJ+yhXb+6JyIJd7upDqjT8KI3iLV0J2a TcKe1N+ddXICw3l6kGX/nK5St6qO7hsi6lg8W2y8xbys+4YlL53AAGGt8Kq/SadhuK65 6MRg== 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:in-reply-to:references :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=SrhgL6ErhD2VJJjnF4ALmSjok7mqYoJNu28PMrD6Dvk=; b=OMPB6asX5AwJv/X1SlukrG2rAihyVMHEEeBu/PH8ckL/YTCf4LTVM3k1L5at4DRNQN AJlx9x9i3DgY8CP1b+N2LcbEKZ43wAqOp+zYMTgrw/6d1JhZ3SQqXpQ2/80d8eWnP0sm WT8OQcyYAxR0QK8e/VCkWNJ2ziKL+3yZFxwcxhwpV0sTxeKeum32IrlqTAkD/7XoMn7a sGlijyLi9ZAriXEKIFyPqDnMVu6uZkuOb7UfpCs92SSb3QnKOiPOSj6sxHam4Zu/jaZ1 NuCx0zQY5pf0867DGVvv0ss08G6/bqzO8ZPmOayRCxqsvj+GJpoqVwuv667jE480p1ud OHng== X-Gm-Message-State: AFeK/H28rxUsY6hoeoGxFAE9Zg6ICs4ESL5EMKGpWZ/8eEQz5nhUwKTJLXXL8DcAyrRR3Q== X-Received: by 10.157.27.253 with SMTP id v58mr772896otv.7.1490861567838; Thu, 30 Mar 2017 01:12:47 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.20.70 with SMTP id h64ls2289652oth.33.gmail; Thu, 30 Mar 2017 01:12:47 -0700 (PDT) X-Received: by 10.157.67.140 with SMTP id t12mr569576ote.7.1490861567000; Thu, 30 Mar 2017 01:12:47 -0700 (PDT) In-Reply-To: <985b9b2a-c734-45eb-95f4-db4dc0d309a1@isocpp.org> X-Original-Sender: rossi.raffaele@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:31894 Archived-At: ------=_Part_3045_308760219.1490861566356 Content-Type: multipart/alternative; boundary="----=_Part_3046_1573441332.1490861566356" ------=_Part_3046_1573441332.1490861566356 Content-Type: text/plain; charset=UTF-8 Wouldn't it be much better to have a concept of Context? I am taking inspiration from python (I know they use it for RAII, but that is a different discussion). The code might look like: void foo() { // do stuff with (unique_lock{mutex}) { // critical code } // other stuff } Then, for prettiness and to avoid unnecessary indentations, when the Context extends till the end of the parent scope, it can just be a declaration: void foo() { with unique_lock{mutex}; // critical code } You can also nest Contexts: void foo() { with unique_lock{mutex1}; with unique_lock{mutex2}; // etc } Also, by having a proper concept of Context, compilers and static analysis tools would have more information available. I don't know about the decomposition side of things, but perhaps using, say @ instead? But I have to admit I still haven't understood the difference with std::ignore (perhaps I have homework to do): auto [x, @, z] = expr; Is anything of this any useful at all? -- 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/00f80877-4564-406b-9dc5-d2d961b8dce3%40isocpp.org. ------=_Part_3046_1573441332.1490861566356 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Wouldn't it be much better to have a concept of C= ontext? I am taking inspiration from python (I know they use it for RAII, b= ut that is a different discussion).

The code m= ight look like:

=
=C2=A0 void foo() {=
=C2=A0 =C2=A0 // do stuff<= /font>
=C2=A0 =C2=A0 with (= unique_lock{mutex}) {
=C2=A0 =C2=A0 }
=C2=A0 =C2=A0 // other stuff
=C2=A0 }

Then, for= prettiness and to avoid unnecessary indentations, when the Context extends= till the end of the parent scope, it can just be a declaration:
=
=C2=A0 void foo() {
=C2=A0 =C2=A0 with uni= que_lock{mutex};
=C2= =A0 =C2=A0 // critical code
=C2=A0 }

You can also nest Contexts= :

=C2=A0 voi= d foo() {
=C2=A0 =C2= =A0 with unique_lock{mutex1};
=C2=A0 =C2=A0 with unique_lock{mutex2};
=C2=A0 =C2=A0 // etc
=C2=A0 }

Als= o, by having a proper concept of Context, compilers and static analysis too= ls would have more information available.

I don= 9;t know about the decomposition side of things, but perhaps using, say @ = =C2=A0instead? But I have to admit I still haven't understood the diffe= rence with std::ignore (perhap= s I have homework to do):

=C2=A0 =C2=A0 auto [x, @, z] =3D expr;

<= /div>
Is anything of this any useful at all?

--
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To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+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/00f80877-4564-406b-9dc5-d2d961b8dce3= %40isocpp.org.
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