220 34671 article Path: news.gmane.org!.POSTED!not-for-mail From: Nevin Liber Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: D0779R0: Proposing operator try() draft 1 paper Date: Fri, 6 Oct 2017 11:05:12 -0500 Lines: 116 Approved: news@gmane.org Message-ID: References: <13df2242-f7dd-405d-b8b9-23b47981c56e@isocpp.org> <59D4D462.9040106@gmx.net> <602e9e20-1d2f-4545-be32-d0234639985c@isocpp.org> <229b9108-ece9-28a1-dbf5-c845e338f557@wanadoo.fr> <32606f9f-1525-43c5-b6f3-50e789b7d234@isocpp.org> <59D5DB4C.90403@gmx.net> <35d99979-247b-48e7-aa83-b8f2fc24a986@isocpp.org> <59D750FF.2090102@gmx.net> <52b64827-d0ba-4ff5-9ea4-d0874b4fb708@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="94eb2c1487be3f77d3055ae30434" X-Trace: blaine.gmane.org 1507305972 1862 195.159.176.226 (6 Oct 2017 16:06:12 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 6 Oct 2017 16:06:12 +0000 (UTC) To: "std-proposals@isocpp.org" Original-X-From: std-proposals+bncBCE35H5S6IDBB2GT33HAKGQEFOMSKXA@isocpp.org Fri Oct 06 18:05:59 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pg0-f72.google.com ([74.125.83.72]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e0V8O-0007FH-12 for gclcip-std-proposals@m.gmane.org; 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[209.85.220.41]) by mx.google.com with SMTPS id x3sor303501plo.126.2017.10.06.09.06.00 for (Google Transport Security); Fri, 06 Oct 2017 09:06:00 -0700 (PDT) Received-SPF: pass (google.com: domain of nliber@gmail.com designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; X-Received: by 10.84.199.194 with SMTP id d2mr2460368plh.346.1507305958896; Fri, 06 Oct 2017 09:05:58 -0700 (PDT) Original-Sender: nliber@gmail.com Original-Received: by 10.100.182.208 with HTTP; Fri, 6 Oct 2017 09:05:12 -0700 (PDT) In-Reply-To: <52b64827-d0ba-4ff5-9ea4-d0874b4fb708@isocpp.org> X-Original-Sender: nevin@eviloverlord.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=YFLSVFMw; spf=pass (google.com: domain of nliber@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=nliber@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:34671 Archived-At: --94eb2c1487be3f77d3055ae30434 Content-Type: text/plain; charset="UTF-8" On Fri, Oct 6, 2017 at 10:44 AM, Niall Douglas wrote: > On Friday, October 6, 2017 at 10:46:43 AM UTC+1, Jens Maurer wrote: >> >> My view on WG21 is that, for at least some people, exceptions are still >> the way to go for error propagation across multiple call frames, one >> argument being that sprinkling your code with "if (error) return" litters >> the CPU's instruction cache and branch predictor with >> almost-never-executed >> stuff. >> > > But coming back to your point, I am well aware of the expert opinion > against this change. I've been at persuading people for something like > eighteen months now, Vicente for years longer again. I found that you can't > convince people based on performance. > When people ask you for numbers and measurements, you say: (I don't mean to brush off your request, but as soon as you cite > benchmarks, people start inspecting the benchmark code, then they start > bike shedding on "oh this is an unrealistic assumption" and "oh that > wouldn't happen in real world code" and so on. Before you know it hundreds > of emails have passed, and effort better expended elsewhere has been > wasted. [...]) Given that you are not willing to provide evidence to back up your claims, your argument boils down to "trust me". I vastly prefer "trust but verify", because in my experience, many people, a lot of which are real experts, have presented things and reasoned things out that turn out not to be valid. It is much, much harder to convince people with unsubstantiated claims on performance than to convince them with substantiated claims about performance. -- Nevin ":-)" Liber +1-847-691-1404 -- 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/CAGg_6%2BPdH1vSfJwucRbjaZrg5OB6uezt-mtHMsB7774CDpPpDg%40mail.gmail.com. --94eb2c1487be3f77d3055ae30434 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Fri, Oct 6, 2017 at 10:44 AM, Niall Douglas <= nialldouglas14@gmail.com> wrote:
On Friday, October 6, 2017 at 10:46:43 AM UTC+1, Jens Maurer wr= ote:
My view on WG21 is that, for at least some people, exc= eptions are still
the way to go for error propagation across multiple call frames, one
argument being that sprinkling your code with "if (error) return&q= uot; litters
the CPU's instruction cache and branch predictor with almost-never-= executed
stuff.

But coming back to your point, = I am well aware of the expert opinion against this change. I've been at= persuading people for something like eighteen months now, Vicente for year= s longer again. I found that you can't convince people based on perform= ance.

When people ask you for n= umbers and measurements, you say:

(I don't mean to brush off your request, but as soon as you cite bench= marks, people start inspecting the benchmark code, then they start bike she= dding on "oh this is an unrealistic assumption" and "oh that= wouldn't happen in real world code" and so on. Before you know it= hundreds of emails have passed, and effort better expended elsewhere has b= een wasted. [...])

Given that you are not w= illing to provide evidence to back up your claims, your argument boils down= to "trust me".=C2=A0 I vastly prefer "trust but verify"= ;, because in my experience, many people, a lot of which are real experts, = have presented things and reasoned things out that turn out not to be valid= ..

It is much, much harder to convince people= with unsubstantiated claims on performance than to convince them with subs= tantiated claims about performance.
--
=C2=A0Nevin ":-)= " Liber=C2=A0 <mailto:nevin@eviloverlord.com> =C2=A0+1-847-691-1404

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