220 40214 article Path: news.gmane.org!.POSTED!not-for-mail From: John McFarlane Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Global operator overriding Date: Sun, 23 Sep 2018 04:54:48 -0700 Lines: 196 Approved: news@gmane.org Message-ID: References: <21428a88-efb7-4648-86c6-5dbf19b96519@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="000000000000db7e570576888af2" X-Trace: blaine.gmane.org 1537703581 19778 195.159.176.226 (23 Sep 2018 11:53:01 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 23 Sep 2018 11:53:01 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDS7B7WQUYOBBFX6TXOQKGQE75PCLHI@isocpp.org Sun Sep 23 13:52:56 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-lj1-f198.google.com ([209.85.208.198]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1g42wW-00053f-Tc for gclcip-std-proposals@m.gmane.org; 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[209.85.220.41]) by mx.google.com with SMTPS id q5-v6sor13123909lff.24.2018.09.23.04.55.01 for (Google Transport Security); Sun, 23 Sep 2018 04:55:01 -0700 (PDT) Received-SPF: pass (google.com: domain of mcfarlane.john@gmail.com designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; X-Received: by 2002:a19:ae15:: with SMTP id f21-v6mr3232249lfc.86.1537703700821; Sun, 23 Sep 2018 04:55:00 -0700 (PDT) In-Reply-To: X-Original-Sender: john@mcfarlane.name X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of mcfarlane.john@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=mcfarlane.john@gmail.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:40214 Archived-At: --000000000000db7e570576888af2 Content-Type: text/plain; charset="UTF-8" On Sun, 23 Sep 2018 at 00:36 Sarfaraz Nawaz wrote: > > return _left + _right; > > > Is this a recursive call? > It looks that way. I'm not sure overflow checking can really be controlled without a custom type. I'm also highly doubtful that throwing an exception is the right thing to do in most cases. Correct code should be avoiding overflow under nearly all circumstances. Therefore, overflow is a bug and should not be handled with exceptions. But certainly the demand for a way to better handle these errors is only growing. Sanitizers cannot catch all overflow and they cannot easily be applied selectively. Users at least need to be able to opt in to reliable diagnostics. On Sat, Sep 22, 2018 at 4:39 PM Denis Kotov wrote: > Hello everyone, > > I have faced with an issue when I want for all numeric types create > general mechanize of checking for overflowing, but to make it optional. > *My Proposal* is to add possibility to override global operators to make > possible to add logic for overflow checking: > > template > constexpr inline auto operator +(TLeft _left, TRight _right) -> decltype(_left + _right) { > if (typeid(decltype(_left + _right)) == typeid(TLeft)) { > // Implementation of checking of overflow > // For example: If overflow throw exception > } else { > // Implementation of checking of overflow > // For example: If overflow throw exception > } > return _left + _right; > } > > What do you think about such solution ? > > -- > 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/21428a88-efb7-4648-86c6-5dbf19b96519%40isocpp.org > > . > -- 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/CAJ2mQS05Y8ezjYnWwdaj7xxa0%3D5etZPKBUvkDNtbXCvt%3Duf_Tg%40mail.gmail.com .. -- 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/CABPJVnR3yCzLeYKxdt33JXM17vKwm-7LvuMOLrFZFWPSgOnpvg%40mail.gmail.com. --000000000000db7e570576888af2 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Sun, 23 Sep= 2018 at 00:36 Sarfaraz Nawaz <nawa= zzz@gmail.com> wrote:

re= turn _left + _right;

Is this=C2= =A0 a recursive call?

It looks th= at way. I'm not sure overflow checking can really be controlled without= a custom type.

I'm also highly doubtful that = throwing an exception is the right thing to do in most cases. Correct code = should be avoiding overflow under nearly all circumstances. Therefore, over= flow is a bug and should not be handled with exceptions.

But certainly the demand for a way to better handle these errors is = only growing. Sanitizers cannot catch all overflow and=C2=A0 they cannot easily be applied selectively. Users at least need to be able t= o opt in to reliable diagnostics.

=
On Sat, Sep 22, 2018 at 4:39 PM= Denis Kotov <r= edradist@gmail.com> wrote:
<= div dir=3D"ltr">
Hello everyone,

I have faced with an is= sue when I want for all numeric types create general mechanize of checking = for overflowing, but to make it optional.
My Proposal is to add possibility to override global operators to m= ake possible to add logic for overflow checking:

template <typename TLeft, typename TRight>
constexpr inline auto operator +(TLeft _left, TRight _right) -> decltype(_left + _right) {
  i=
f (typeid(decltype(_left + _right))=
 =3D=3D typeid(TLeft))=
 {
    // Implementation=
 of checking of overflow
    // For example: If overflow t=
hrow exception
  } else {
    // Implementation of checking o=
f overflow
    // For example: If overflow throw exception
  }
  return _left + _right;}

What do you think about such solution ?
<= /div>

--
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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/21428a88-efb7-= 4648-86c6-5dbf19b96519%40isocpp.org.

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