220 13893 <543E7CB4.7020003@gmx.net> article Path: news.gmane.org!not-for-mail From: Jens Maurer Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Comment on N4191 - Folding expressions (Sutton, Smith) Date: Wed, 15 Oct 2014 15:55:00 +0200 Lines: 66 Approved: news@gmane.org Message-ID: <543E7CB4.7020003@gmx.net> References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1413381317 16032 80.91.229.3 (15 Oct 2014 13:55:17 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 15 Oct 2014 13:55:17 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDPMTYGK64JRBN7Z7GQQKGQE73Y5IWA@isocpp.org Wed Oct 15 15:55:09 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wg0-f70.google.com ([74.125.82.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XeP2i-0003DS-Pj for gclcip-std-proposals@m.gmane.org; Wed, 15 Oct 2014 15:55:09 +0200 Original-Received: by mail-wg0-f70.google.com with SMTP id a1sf760481wgh.5 for ; Wed, 15 Oct 2014 06:55:05 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:message-id:date:from:user-agent:mime-version:to :subject:references:in-reply-to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe:content-type; bh=mE4qa+vuW0/BLIyvBk4t0EsLMvNAUj+JgYB+J+j3C+g=; b=aPNklcOIw13qrBhTZfTkGV9wjT62aNxXXfH4vgM0h8aGo11oEA/5syuka16hUDhfCu pxkfylUbtFKrCSlvodTy9k7qCCOKwMeEX/1iR9DscNM3oavqrTjxMagD256ZgnvAPsew lNobT4yTzdaS/wmElik2a003VNX92uXJqisoQqBN8VDVUCfbvCTXZ+4vnszrRVu/7M43 NWrjPEwEC8Y6L1XUKRDrAv4I6hMIFd+RFjfDHcrUr0igd9H1wIKyOEuOVeSQPDP7JLk/ M7/K5f5y1f3t6pYWO22H/yisKUnVD4NroKvyLJun3Nyv7rSZtreCLx9VoqaMBGd1aUHS 1W3Q== X-Gm-Message-State: ALoCoQnzXMbQoCXRqWwjYzYrPC97HZbi3RDrwG7gIxNk1l+jal8y55TT5wYC3+DmRnDokTE9por0 X-Received: by 10.180.19.198 with SMTP id h6mr99285wie.5.1413381305323; Wed, 15 Oct 2014 06:55:05 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.152.88.13 with SMTP id bc13ls65346lab.21.gmail; Wed, 15 Oct 2014 06:55:02 -0700 (PDT) X-Received: by 10.152.20.199 with SMTP id p7mr12494474lae.49.1413381302942; Wed, 15 Oct 2014 06:55:02 -0700 (PDT) Original-Received: from mout.gmx.net (mout.gmx.net. [212.227.17.20]) by mx.google.com with ESMTPS id xt8si30516870lac.122.2014.10.15.06.55.02 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 15 Oct 2014 06:55:02 -0700 (PDT) Received-SPF: pass (google.com: domain of Jens.Maurer@gmx.net designates 212.227.17.20 as permitted sender) client-ip=212.227.17.20; Original-Received: from [192.168.2.100] ([92.208.227.175]) by mail.gmx.com (mrgmx101) with ESMTPSA (Nemesis) id 0LwF9u-1YE9lo0FJe-017zOb for ; Wed, 15 Oct 2014 15:55:02 +0200 User-Agent: Mozilla/5.0 (X11; Linux i686; rv:6.0.1) Gecko/20110830 Thunderbird/6.0.1 In-Reply-To: X-Provags-ID: V03:K0:gdCinSAmcHrdnR9J6R4dCcNWOMHFUKJSfQH6gxyim5+95H2v42b 8wmOxv+gDZQBLI4W7h65/PYXXYGu6i+NicmrrxlgQdEybkI7aF1iRljB/sJLyz6KT/6tpCp bmjC9v4T9Xn35El6Ll78XTYx2ujx5cZWlzVBdAD2lmK3VmxccGLHdk26tGk86IjFqDh/AhD LOE/wBsFbmgKJITtvFzwA== X-UI-Out-Filterresults: notjunk:1; X-Original-Sender: Jens.Maurer@gmx.net X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of Jens.Maurer@gmx.net designates 212.227.17.20 as permitted sender) smtp.mail=Jens.Maurer@gmx.net 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:13893 Archived-At: I'd prefer not to derail N4191 with additional features or depend on other proposals. It seems your suggestions are purely add-on and should be handled in a separate paper. Jens On 10/15/2014 01:45 PM, George Makrydakis wrote: > Two observations on N4191: > > First, given that the paper proposes making catamophisms (left and right folds) as a primary language construct, > is there a reason as to why this should be limited to just values and not types as well? Instead of an operator, a > template template parameter could be used as is the case for the following examples of valid C++11 code for > providing the "folded" instantiation in this case: > > #include > > template< template class F > , typename A, typename B, typename C, typename D> > void fun (F>>) > { printf("folding in one way...\n"); } > > template< template class F > , typename A, typename B, typename C, typename D> > void fun (F,C>,D>) > { printf("folding in another way...\n"); } > > template > struct funny {}; > > int main() { > fun(funny>>()); > fun(funny,int>,long>()); > return {}; > } > > With the intention of expanding this to packs of course, manipulating the tripple-dot syntax. Could N4191 address > this as well in a future iteration? > > Second, why should the folding expressions be limited to operators using (... + args) and not functions as well, > using (... f args) as well with f being a function identifier, or some sort of other syntax including that f function > can be used with, inspired for example from N4165 / N4174 (uniform function call syntax)? > > Regards, > > George > > -- > > --- > 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/. -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. 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