220 33121 article Path: news.gmane.org!.POSTED!not-for-mail From: Jonathan Coe Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Struture dereference operator as fallback for missing structure reference Date: Wed, 5 Jul 2017 09:04:34 +0100 Lines: 189 Approved: news@gmane.org Message-ID: References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 (1.0) Content-Type: multipart/alternative; boundary=Apple-Mail-F8FD5D6E-76E1-4348-A312-AB05D8390CA8 Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1499241884 9910 195.159.176.226 (5 Jul 2017 08:04:44 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 5 Jul 2017 08:04:44 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC2JVFPBRAHBBFN36LFAKGQELCOJLFA@isocpp.org Wed Jul 05 10:04:39 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-lf0-f69.google.com ([209.85.215.69]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dSfIX-0002Bp-Je for gclcip-std-proposals@m.gmane.org; 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[2a00:1450:400c:c09::242]) by mx.google.com with ESMTPS id e81si9465772wma.64.2017.07.05.01.04.37 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 05 Jul 2017 01:04:37 -0700 (PDT) Received-SPF: pass (google.com: domain of jonathanbcoe@gmail.com designates 2a00:1450:400c:c09::242 as permitted sender) client-ip=2a00:1450:400c:c09::242; Original-Received: by mail-wm0-x242.google.com with SMTP id p204so30781737wmg.1 for ; Wed, 05 Jul 2017 01:04:37 -0700 (PDT) X-Received: by 10.28.174.66 with SMTP id x63mr6626464wme.12.1499241877043; Wed, 05 Jul 2017 01:04:37 -0700 (PDT) Original-Received: from [10.78.173.102] ([149.254.184.134]) by smtp.gmail.com with ESMTPSA id 80sm13233742wmg.17.2017.07.05.01.04.35 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 05 Jul 2017 01:04:35 -0700 (PDT) In-Reply-To: X-Mailer: iPhone Mail (14F89) X-Original-Sender: jonathanbcoe@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.b=Au1EDXPv; spf=pass (google.com: domain of jonathanbcoe@gmail.com designates 2a00:1450:400c:c09::242 as permitted sender) smtp.mailfrom=jonathanbcoe@gmail.com; dmarc=pass (p=NONE sp=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:33121 Archived-At: --Apple-Mail-F8FD5D6E-76E1-4348-A312-AB05D8390CA8 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable > On 5 Jul 2017, at 08:28, Micha=C5=82 Dominiak wrote: >=20 > This would: >=20 > 1) Make it very easy to refer to the wrong field accidentally (of the wra= pper instead of of the wrapped object). > 2) Make it so that a change in the wrapper's interface (say, adding a fie= ld) changes the semantics of the code in a potentially silent manner - no-o= ne would ever again be able to add to the interface of a type exposing the = -> operator. >=20 > No. >=20 > Educate your programmers, don't hire incompetent people. It's really that= simple. >=20 >> On Wed, Jul 5, 2017 at 9:24 AM Daemon Snake wrote: >> Hi, >> I think a lot of us feel like the "->" operator feels quite archaic, >> so it's not uncommon to use the '.' operator while using a pointer or a = shared or unique pointer by accident. >> The result is a compile error with an indication on where the mistake wa= s made along with a "(maybe you meant to use '->' ?)" error message. >>=20 >> For people coming from languages like Java it's a recurring error, one t= hat frankly seem a bit dull and really annoying for big projects. >>=20 >> My "solution" would be really simple to implement I believe. >> If said error is detected instead of stopping the compilation and issuin= g the error we could simply fallback on the struct dereference operator ("-= >"). >> This wouldn't have any impact on legacy, or C code (or only malformed on= e). >> It would allow the implicit declaration of the overloading of the struct= ure reference operator. >> Also make optional the "->" operator for a less cumbersome syntax at the= end. >> The compile time impact would be minimal as it would only happen in fail= states and the computation is not really complex. >>=20 >> So what do you think ? >> Is there issues I haven't considered ? >>=20 To me '->' suggests that the object could be in a null state, '.' does not.= =20 I'd be concerned about lost information for readers if '.' no longer implie= d non-nullable. >> Thanks in advance. >> Bastien Penavayre >> --=20 >> You received this message because you are subscribed to the Google Group= s "ISO C++ Standard - Future Proposals" group. >> To unsubscribe from this group and stop receiving emails from it, send a= n 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/iso= cpp.org/d/msgid/std-proposals/e2d61492-c318-46b1-89e1-94f9697875dd%40isocpp= ..org. >=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= 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/isoc= pp.org/d/msgid/std-proposals/CAPCFJdSzcO6_4fWYE6SjDpTKTuU1NsGdZCmMzEVJF%3DL= ajvgpew%40mail.gmail.com. --=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/A6913DF9-37C5-4465-B663-3FC808583F61%40gmail.com= .. --Apple-Mail-F8FD5D6E-76E1-4348-A312-AB05D8390CA8 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On 5= Jul 2017, at 08:28, Micha=C5=82 Dominiak <griwes@griwes.info> wrote:

This would:

1) Make it very= easy to refer to the wrong field accidentally (of the wrapper instead of o= f the wrapped object).
2) Make it so that a change in the wrapper= 's interface (say, adding a field) changes the semantics of the code in a p= otentially silent manner - no-one would ever again be able to add to the in= terface of a type exposing the -> operator.

No.=

Educate your programmers, don't hire incompetent = people. It's really that simple.

=
On Wed, Jul 5, 2017 at 9:24 AM Daemon Snake <swac31@gmail.com> wrote:
Hi,
I think a lot of us feel li= ke the "->" operator feels quite archaic,
so it's not uncommon t= o use the '.' operator while using a pointer or a shared or unique pointer = by accident.
The result is a compile error with an indication on = where the mistake was made along with a "(maybe you meant t= o use '->' ?)" error message.

For people coming from languages like Java= it's a recurring error, one that frankly seem a bit dull and really annoyi= ng for big projects.

My "solution" w= ould be really simple to implement I believe.
If said error is de= tected instead of stopping the compilation and issuing the error we could s= imply fallback on the struct dereference operator ("->").
This= wouldn't have any impact on legacy, or C code (or only malformed one).
It would allow the implicit declaration of the overloading of the st= ructure reference operator.
Also make optional the "->" operat= or for a less cumbersome syntax at the end.
The compile time impa= ct would be minimal as it would only happen in fail states and the computat= ion is not really complex.

So what do you think ?<= /div>
Is there issues I haven't considered ?

=

To me '->= ;' suggests that the object could be in a null state, '.' does not. 
I'd be concerned about lost information for readers if '.' no long= er implied non-nullable.

= Thanks in advance.
Bastien Penavayre

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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/e2d61492-c318-= 46b1-89e1-94f9697875dd%40isocpp.org.

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