220 32398 article Path: news.gmane.org!.POSTED!not-for-mail From: "Vicente J. Botet Escriba" Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Solving the std::swap embarrassment*? 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[80.12.242.135]) by mx.google.com with ESMTPS id k127si8736058wmg.128.2017.05.11.12.37.02 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 11 May 2017 12:37:03 -0700 (PDT) Received-SPF: neutral (google.com: 80.12.242.135 is neither permitted nor denied by best guess record for domain of vicente.botet@wanadoo.fr) client-ip=80.12.242.135; Original-Received: from imac-de-vicente-botet-escriba.home ([2.10.138.79]) by mwinf5d76 with ME id K7d11v00y1ixzca037d2NH; Thu, 11 May 2017 21:37:02 +0200 X-ME-Helo: imac-de-vicente-botet-escriba.home X-ME-Auth: dmljZW50ZS5ib3RldEB3YW5hZG9vLmZy X-ME-Date: Thu, 11 May 2017 21:37:02 +0200 X-ME-IP: 2.10.138.79 In-Reply-To: <201705111140.05330.marc.mutz@kdab.com> X-Original-Sender: vicente.botet@wanadoo.fr X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 80.12.242.135 is neither permitted nor denied by best guess record for domain of vicente.botet@wanadoo.fr) smtp.mailfrom=vicente.botet@wanadoo.fr 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:32398 Archived-At: Le 11/05/2017 =C3=A0 11:40, Marc Mutz a =C3=A9crit : > On Saturday 06 May 2017 15:41:53 Vicente J. Botet Escriba wrote: >> So to answer to your comment.we want a single point that is able to >> ensure some constraints (Method Pattern) and call to the specific >> customized part. Adding overload in std will not satisfy these goal. I >> believe the goals are desirable. > You are already allowed to "customise" a) every std class template (by fu= ll or > partial specialisation, which needs to mention a user type), b) every std > function template (by full specialisation, which needs to mention a user > type). I was aware that we can specialize some classes, but not all, and even=20 less the full specialize a std function. Could you point me to the=20 references? Nevertheless this doesn't solve the customization points we=20 are talking of. > And there's no central dispatch to enforce constraints there, either > (and $DEITY forbid someone starts to specialise std::allocator, or > std::is_pod, ...). > > I can already specialise std::reverse for any concrete instantiation of Q= List, > by full specialisation. The embarrassment is that I can't do this for the > QList template itself (ie. all instantations of it). I guess you are not happy then. > > So, from my POV of developer-in-the-trenches all that talk about customis= ation > points, associcated with concepts, is just hot air. I will not talk about what developers think. I consider my self a=20 library developer and I don't agree with you here. In generic programming we need customization points in one way or another. > The issue is why overloads > of std function (s|templates), which are the moral equivalent of partial = class > template specialisation, are not allowed, and why some complex years-in-t= he- > future mythical language feature is needed, to artifically constrain some= thing > that's already unconstrained. > I believe someone has already responded to this question, but maybe it=20 was in another thread. Vicente --=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/f8add216-a4e1-9a47-9d06-3378d5d48e01%40wanadoo.f= r. .