220 26381 <2308f718-9fcb-445f-974c-9acc9c0aa605@isocpp.org> article Path: news.gmane.org!not-for-mail From: Nicol Bolas Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: template Date: Sat, 25 Jun 2016 10:56:43 -0700 (PDT) Lines: 118 Approved: news@gmane.org Message-ID: <2308f718-9fcb-445f-974c-9acc9c0aa605@isocpp.org> References: <58413fd1-653d-4171-a250-baa99c0a597b@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_205_1149690343.1466877403771" X-Trace: ger.gmane.org 1466877417 15475 80.91.229.3 (25 Jun 2016 17:56:57 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 25 Jun 2016 17:56:57 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCEKFTV6ZUMBBXMLXO5QKGQE7NQXXAY@isocpp.org Sat Jun 25 19:56:52 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-io0-f197.google.com ([209.85.223.197]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1bGrp1-0000lD-C5 for gclcip-std-proposals@m.gmane.org; Sat, 25 Jun 2016 19:56:47 +0200 Original-Received: by mail-io0-f197.google.com with SMTP id x68sf281868663ioi.0 for ; Sat, 25 Jun 2016 10:56:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=yCuCC9yBT50CwoLk0IcfFsLEQvJA8ckgJujw+XRTPQ8=; b=J6cxv2QjQbPTLlNIowahRIZbpnpFk7yNp/aLG74oRfC1zzg+Lc8p+9+4UJ82v9gM+g LJnw/K6Jm3xsT/0EQd7AsN+K5AjSkAPh1mSNqBA+53aJCJRtX6l/ZJHyo0/esq7++oN7 ZzFaFY8+bpnQ8t0vtgVWHzc0c4ZRXhhyIEWfaOd56XlLlDfaTg9vCaZqcixWJUS6q/nb 38vPkQ8V/S6/ZrVejLMhgKk3YFBGIGoGJ7uUkx2zyZfyC5t7T5fw5UoJ1DIqHs9dUoZD VDVIpFu5K0e+4C5HNSX2V2nrH6GyuzzK/FYtSpgDZsHnpuRZrV5uyPglMi4I74slkmUz 5vDA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=yCuCC9yBT50CwoLk0IcfFsLEQvJA8ckgJujw+XRTPQ8=; b=TKv5S/uq72iL3ZwIZVazxLUVMvyh+0bzii753XYrfdmVhZ9SQFNsJ0E8ycn8bHXCio o8ND27UCmsVKKkzv/lsn5plU0X1tkxV3jNSkzGFRHaH6FBc0LS+M4cWJ5N/SxZ6ETcSa EHgy22jNKa7HUa+4lho7UbOq41D4zYqhDz+sSko+l2qKCN/zOo+5s+QjzYSd9YdqHdRT KyditYmGwKLALuNI5O9/0iZ+TpoELgiLjclbM4gwF8xYo6DH4YggIeLesXYDZaFBYz9R sRfE1uWfj1myQXDmU6F1rR9awkNRe905WRaU/aLJObp6YxLny3cN4iYC76DofPzNBz2e arDg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:message-id:in-reply-to:references :subject:mime-version:x-original-sender:reply-to:precedence :mailing-list:list-id:x-spam-checked-in-group:list-post:list-help :list-archive:list-subscribe:list-unsubscribe; bh=yCuCC9yBT50CwoLk0IcfFsLEQvJA8ckgJujw+XRTPQ8=; b=E6wz1EbYVbR+WLQdZr3cTo9+YUsHrdGtxia4pqvh7pNiBXRCQAYzhb92qMWJm7pRtY VOYM0/i+7VlCDa/JLOm2UYpMjjYV/JGl0IO2yMuv4AUExj9TjY06ll+mHUqJw+00vBGx vIiyqLZ7uiQCBX3Y959TKkTE9oF2Ue3a/QQTvQgQ3hQ/GwH9kk/aUus0TZi7Nn5zZGOk 4hLiIUk0groFkhaTFu5c3qlg/yFcqr/VtJIoEOo78H2G23HxZUuRNcI6UVcPlkNPGHBk v9lgphde5/HLowmeKUmOxSJXTlbPQ2setSDMD8o/DHps1z2nJ+J2lq/Vy98bcuNDT5M7 r3lQ== X-Gm-Message-State: ALyK8tIhlHbvHXDldW6lTAZl7z/DM5EJ6JTJRWu2oap2yBFGWXsiO6nNIje09O+B9QAT/w== X-Received: by 10.36.73.170 with SMTP id e42mr3926492itd.4.1466877406027; Sat, 25 Jun 2016 10:56:46 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.36.129.6 with SMTP id q6ls554286itd.44.gmail; Sat, 25 Jun 2016 10:56:45 -0700 (PDT) X-Received: by 10.36.17.15 with SMTP id 15mr113943itf.10.1466877405019; Sat, 25 Jun 2016 10:56:45 -0700 (PDT) In-Reply-To: <58413fd1-653d-4171-a250-baa99c0a597b@isocpp.org> X-Original-Sender: jmckesson@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:26381 Archived-At: ------=_Part_205_1149690343.1466877403771 Content-Type: multipart/alternative; boundary="----=_Part_206_1122936876.1466877403772" ------=_Part_206_1122936876.1466877403772 Content-Type: text/plain; charset=UTF-8 On Saturday, June 25, 2016 at 12:14:28 PM UTC-4, Guillaume Racicot wrote: > > After reading P0127R1 > , I > wondered if auto& as a template parameter is be possible too. It would > allow things like this: > > template > struct Foo { > void display() { > std::cout << "value: " << thing << " address: " << &thing << std:: > endl; > } > }; > > extern int i; > > Foo foo; > > Is this thing already possible in the current proposal? > No. The paper merely adds deduction of the type of non-type template parameters based on the value passed. It does not change what valid non-type template parameters can be. You couldn't do `template` before, so you can't do it now. You can make it a pointer if you want, but that would require doing `Foo<*i>`. -- 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/2308f718-9fcb-445f-974c-9acc9c0aa605%40isocpp.org. ------=_Part_206_1122936876.1466877403772 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Saturday, June 25, 2016 at 12:14:28 PM UTC-4, Guillaume= Racicot wrote:
After reading=C2=A0P0127R1, I wondered if auto& as a template parameter= is be possible too. It would allow things like this:

template= <auto& thing>
<= /span>struct <= /span>Foo {
=C2=A0= =C2=A0 void display() {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 std::<= /span>cout <= ;< &= quot;value: " << thing << " address: " << &thing << std::endl;
=C2=A0 =C2=A0 }
};

extern<= span style=3D"color:#000"> int i;

Foo<i> foo;

Is this thing already possible in the current proposal?

No. The paper merely adds deduction of the type of non-type = template parameters based on the value passed. It does not change what vali= d non-type template parameters can be.

You couldn't do `template= <int &i>`=C2=A0 before, so you can't do it now. You can make = it a pointer if you want, but that would require doing `Foo<*i>`.
=

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