220 5298 article Path: news.gmane.org!not-for-mail From: Martinho Fernandes Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Overloaded Declarators Date: Fri, 5 Jul 2013 15:57:23 +0200 Lines: 81 Approved: news@gmane.org Message-ID: References: <82b89c5e-ce4e-49c0-82b2-d6032631e3e3@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1373032645 26869 80.91.229.3 (5 Jul 2013 13:57:25 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 5 Jul 2013 13:57:25 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDXL3FEUYQARBQ5B3OHAKGQEK4HOGTA@isocpp.org Fri Jul 05 15:57:26 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yh0-f70.google.com ([209.85.213.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Uv6Vp-000332-7O for gclcip-std-proposals@m.gmane.org; Fri, 05 Jul 2013 15:57:25 +0200 Original-Received: by mail-yh0-f70.google.com with SMTP id l109sf2987992yhq.9 for ; Fri, 05 Jul 2013 06:57:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-beenthere:mime-version:in-reply-to:references:date:message-id :subject:from:to:x-original-sender:x-original-authentication-results :reply-to:precedence:mailing-list:list-id:x-google-group-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type:content-transfer-encoding; bh=uilOTOhzunmOtrv5cKtZNVcCTGcSsI1ylcE2p7vCHAQ=; b=dBeTtucuv9Z1tI8z6gkQokKXXMl2RuacYPu4jxxGee9ytxm2Vac3OPg++rSpq2Rt07 mkOH5cqAQqv/IlbnfLmBQqw35/bWFMDcdzKDoXSHsTOUGZUlScmA7QXJRQ5UgB/yBVDQ RLPhHe3n8/I5lIJ/7V5FXpITVx6ffAUl1a3/3hSOJhGDTKJVlTv/t+pzrYOiKPiM+06T VWVHjBx7+FFiKUJ9+c/rFciHxA+0k3IOMNP7LKQdl6kW28I16LvNAmKdsNw5VURd+mHw NJfnZYTBOMtwlGUWRdl6hQ9wmaA8Q9uWshrIJTakdn975pAXUZavye89nbhU7rovjQVD KFTA== X-Received: by 10.236.55.129 with SMTP id k1mr5276610yhc.1.1373032644348; Fri, 05 Jul 2013 06:57:24 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.49.120.234 with SMTP id lf10ls938162qeb.49.gmail; Fri, 05 Jul 2013 06:57:23 -0700 (PDT) X-Received: by 10.49.58.70 with SMTP id o6mr6359767qeq.1.1373032643665; Fri, 05 Jul 2013 06:57:23 -0700 (PDT) Original-Received: from mail-qe0-x229.google.com (mail-qe0-x229.google.com [2607:f8b0:400d:c02::229]) by mx.google.com with ESMTPS id s10si2272422qan.126.2013.07.05.06.57.23 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 05 Jul 2013 06:57:23 -0700 (PDT) Received-SPF: pass (google.com: domain of martinho.fernandes@gmail.com designates 2607:f8b0:400d:c02::229 as permitted sender) client-ip=2607:f8b0:400d:c02::229; Original-Received: by mail-qe0-f41.google.com with SMTP id b4so1240493qen.14 for ; Fri, 05 Jul 2013 06:57:23 -0700 (PDT) X-Received: by 10.49.83.37 with SMTP id n5mr6330694qey.57.1373032643568; Fri, 05 Jul 2013 06:57:23 -0700 (PDT) Original-Received: by 10.49.94.238 with HTTP; Fri, 5 Jul 2013 06:57:23 -0700 (PDT) In-Reply-To: <82b89c5e-ce4e-49c0-82b2-d6032631e3e3@isocpp.org> X-Original-Sender: martinho.fernandes@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of martinho.fernandes@gmail.com designates 2607:f8b0:400d:c02::229 as permitted sender) smtp.mail=martinho.fernandes@gmail.com; dkim=pass header.i=@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:5298 Archived-At: What if I want an actual pointer now? Mit freundlichen Gr=FC=DFen, Martinho On Fri, Jul 5, 2013 at 8:32 AM, wrote: > If we view for a moment the various parts of a declarator as operations o= n > types: > > T*: T -> pointer-to-T > T&: T -> lvalue-reference-to-T > T&&: T -> rvalue-reference-to-T > T[]: T -> array-of-T > T(): T -> function-returning-T > and so forth > > These operations take one or more types as input and produce a type as > output. > > This is not dissimilar to an alias template: > > template > using MakePointer =3D T*; > > template > using MakeReference =3D T&; > > In fact we could almost say that functions are to the built-in expression > operators, as alias templates are to the built-in declarators. > > So the proposed feature "Overloaded Declarators" is to enable a user-defi= ned > alias template to redefine the built-in meaning of a declarator. > > Overloaded Declarators are to the built-in declarators, as Overloaded > Operators are to the built-in expression operators: > > struct Foo{} > > template > using operator* =3D shared_ptr; > > Foo* p; // p has type shared_ptr > > The above shows a key use case, specializing the declarator `T*` to > designate a user-defined smart pointer class instead of pointer-to-T for > some set of types. > > Just a random idea. > > Enjoy, > Andrew. > > -- > > --- > 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. > Visit this group at > http://groups.google.com/a/isocpp.org/group/std-proposals/. > > --=20 ---=20 You received this message because you are subscribed to the Google Groups "= ISO C++ Standard - Future Proposals" group. 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