220 30776 article Path: news.gmane.org!.POSTED!not-for-mail From: TONGARI J Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Make Typedef Great Again Date: Sun, 5 Feb 2017 04:56:11 -0800 (PST) Lines: 241 Approved: news@gmane.org Message-ID: References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_4584_265284119.1486299371968" X-Trace: blaine.gmane.org 1486299373 4831 195.159.176.226 (5 Feb 2017 12:56:13 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 5 Feb 2017 12:56:13 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCC3NA775MLBB3GB3TCAKGQEWDNXXXA@isocpp.org Sun Feb 05 13:56:09 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yw0-f199.google.com ([209.85.161.199]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1caMMS-00013r-08 for gclcip-std-proposals@m.gmane.org; Sun, 05 Feb 2017 13:56:08 +0100 Original-Received: by mail-yw0-f199.google.com with SMTP id q71sf67113653ywg.1 for ; Sun, 05 Feb 2017 04:56:14 -0800 (PST) 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=dDLCvUr8nCD0K5Zwvgiamb7CT+KVC57pDBEGPZ505Lc=; b=OFwDjtBr+stkTH5UWrzI4dJy2mlpcp/NYpWRo/wtFrI51RBM3eI5zn/czIKLmz8yjs XJddvQME3w2VAtQBn9dMhOo7Xh+qmT4Ybmg0CG9F9jTpYBOHH9cWOu8rDSzKDD+JFad3 BCtyADHO/6Fc8mJmpXodjg0s9KwwamcPU0da4Tg6/mOCCx4hcWKFm0vZE0pLYpVvIEGY OB0i7FO/oeqzIJzVdmWkvYw+XCcbHTSqGb71VALaU2V9xvYyU+aN0YMtc1F8w0xXGfUF d3O0UcApHsJpGQ2dv5DRJZT8wefV71vLcJWYsMLVQGEifCoNc5XrvlMFu5jGyuzbyIRk TLGQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; 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=dDLCvUr8nCD0K5Zwvgiamb7CT+KVC57pDBEGPZ505Lc=; b=O8KQPTuNNRAMLAGIS1upaB0b70N7sSZdij96dVlWv5/hn/VGaSMpGUXhkMWCLYYGzD ItaFEHnauRcz/RR96FxUDXcG32EkKcGGhbN5aSzfnbzQE0bEZ/sY99//MVx2jNNh4buW 3YiYOzSIOiBKD1QSXE1N1hhazFLcKZ06TzJJ9sxfPQWJ6UR/JmFK0CYG9JYru6qK1Ldt 5uz7RPj9iWawXQ82GouJvMtMeZI36qhistO/MNs7m04bhPrbKJnqpFWRyEx+F6pD4/Dl PRMGZMqrsSMzhVePq9wKdP6r2zhNAT3l9QSvAROANC85iKemV8XrA63dEqZFhTuvvImn 7maQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; 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=dDLCvUr8nCD0K5Zwvgiamb7CT+KVC57pDBEGPZ505Lc=; b=LawihblPo3ngraFHjrFvZoV710/t6RkXkWnNExGzpdUvMRkCMBfv7UsqojWzO4Ei4M ar3MDDPrOrrhEIjg2nsx0UBvcKFwRBKF8M82IrdijBg+Lp0AKKitpc+qI1+NTuTtRoUc gniyTp3w5JipNOF+zouCQFAuLD9tqIZH+Iouok0xN1k1QTDKD0foqoqrJ5dafnDwvOlP MOnkfp31hnf/aTf/2du0OGFtYB6O0GQ9+x8SxYExm0uuiaor00jn4DBZoFYxj5Ql5hig lOQPCbF5Urn2xotA+PgSUG2BH71/qMXeWpPMoAtg8KPz6seK8xEsRpVJf+PhIrjkc120 BIxw== X-Gm-Message-State: AIkVDXI9NXL/3C2oNdgo9cJ5xJQlA2qNigZfDxAky2wzsO8tgRpuIkGIXWcG42tbl9RdaQ== X-Received: by 10.129.179.202 with SMTP id r193mr1348829ywh.162.1486299373316; Sun, 05 Feb 2017 04:56:13 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.17.154 with SMTP id v26ls11040818otf.0.gmail; Sun, 05 Feb 2017 04:56:12 -0800 (PST) X-Received: by 10.157.18.211 with SMTP id g77mr318098otg.14.1486299372639; Sun, 05 Feb 2017 04:56:12 -0800 (PST) In-Reply-To: X-Original-Sender: tongari95@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:30776 Archived-At: ------=_Part_4584_265284119.1486299371968 Content-Type: multipart/alternative; boundary="----=_Part_4585_2063778322.1486299371969" ------=_Part_4585_2063778322.1486299371969 Content-Type: text/plain; charset=UTF-8 On Sunday, February 5, 2017 at 6:41:36 PM UTC+8, Vicente J. Botet Escriba wrote: > > I'm not saying the feature is not needed. I believe however that the > proposal needs to compare what it is currently doable. > > Couldn't we use the existing language already > > template::type > > T f() // yay! > { > // Use `T` from now on... > } > > In this case, it's just an alternative w/o (ab)using the template param, like how concept-lite tries to eliminate enable_if trick. > template::type> > class Derived : public Base // yay! > { > // Use `Base` from now on... > } > This does not work if "blahblah...", is actually a template parameter pack, which has to be the last one. > In parameter list: > template > void f(typedef SomeTemplate T a, T b); // yay! > > I'm not sure the blahblah could be inferred > > Do tou mean > > > template > void f(U, typedef SomeTemplate T a, T b); > I mean something like: template void f(typedef std::tuple T a, T b); f(std::make_tuple(1, 2), std::make_tuple(3, 4)); //Args == {int, int}, T == std::tuple -- 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/fc42405f-b5de-492a-9e7e-e191a6dd975c%40isocpp.org. ------=_Part_4585_2063778322.1486299371969 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Sunday, February 5, 2017 at 6:41:36 PM UTC+8, Vicente J= .. Botet Escriba wrote:=C2=A0
I'm not saying the feature= is not needed. I believe however that the proposal needs to compare what it is currently doable.

Couldn't we use the existing language already

template<blahblah..., typename T =3D typename MetaFunc<blahblah= ...>::type = >
T f() // yay!
{
=C2=A0 =C2=A0 // Use `T` from= now on...
}
In this case,= it's just an alternative w/o (ab)using the template param, like how co= ncept-lite tries to eliminate enable_if trick.
=C2=A0
template<blahblah..., typename Base=3Dtypename MetaFunc<blahblah...>::type= >
class Derived : pu= blic Base // yay!
{
=C2=A0 =C2=A0 // Use `Base` f= rom now on...
}
=C2=A0
This does not work if "blahblah...", is actually a template parameter pa= ck, which has to be the last one.
=20
In parameter list:
template<blahblah...>
void f(typedef SomeTemplate<blahblah...> T a, T b); // yay!

I'm not sure the blahblah could be inferred

Do tou mean


template<class U>
void f(U, typedef SomeTemplate<U> T a, T b);

I mean something like:
template<class... Args>
void f(typedef std::tuple<Args...> T a, T b= );

= f(std<= /span>::make_tuple(1, 2), std::make_tuple(3,= 4)); //Args =3D=3D {int, int}, T =3D=3D std::tupl= e<int, int>

--
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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/fc42405f-b5de-492a-9e7e-e191a6dd975c= %40isocpp.org.
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