220 14118 article Path: news.gmane.org!not-for-mail From: =?UTF-8?Q?Germ=C3=A1n_Diago?= Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Again on constexpr stuff Date: Wed, 22 Oct 2014 04:55:05 -0700 (PDT) Lines: 93 Approved: news@gmane.org Message-ID: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_3842_1606298177.1413978905985" X-Trace: ger.gmane.org 1413978915 30312 80.91.229.3 (22 Oct 2014 11:55:15 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 22 Oct 2014 11:55:15 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDC2VXM4YYDRBG5WT2RAKGQEVBLZX2Q@isocpp.org Wed Oct 22 13:55:10 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pa0-f71.google.com ([209.85.220.71]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XguVS-0008AR-5y for gclcip-std-proposals@m.gmane.org; Wed, 22 Oct 2014 13:55:10 +0200 Original-Received: by mail-pa0-f71.google.com with SMTP id rd3sf7663699pab.6 for ; Wed, 22 Oct 2014 04:55:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:message-id:subject:mime-version:x-original-sender :reply-to:precedence:mailing-list:list-id:list-post:list-help :list-archive:list-subscribe:list-unsubscribe:content-type; bh=kKAhUsCEKM44tPFaTL3C7r0BK4zYDft7szpZjEFayZg=; b=hxV9oHdtGPntlYmggYF8a2P5ffe0XUWfgoQsQ2fq6yWOxrFnEOsVRXAsla1Q1tDgov XB4UKzIRIrpBa73IICz/0/YzIXINlSjvXHv3+vfK4zrCar+D0Hp1sUudRoiB2koxMZQm +dKNPkp/EVHLca5iu0VKeWA9GhVxzpyXF8ZJus7CCn/RWD7CIgMavdubeeItGZh8xFar XlMLQKP/waOFoxjJD6ZaW3wI3LHXy7YYZxvqJlZvj809CvcP9/r5kf4zxFrgX8Ooz7gm jPY5ctqZLTtF4HPqOZczFmtf3cHlNYa/UdQgJWe1/0pgqPPN20hWd77MJ1iMTC13w8Yo txzw== 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:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=kKAhUsCEKM44tPFaTL3C7r0BK4zYDft7szpZjEFayZg=; b=Ux7M6s6shV57uv2Ou8t2EqTLgp4bvjk/OPZGWqypbjIIB7Jq9vDwPrB6ChMMDd1w6p GNMz2dMPy9aFggFD3paDOVjvMCZl7YUsMdorA3tG1ipPwJgcrkB01qC9ISoltq9T8FDO n465ZXjkut5FgsxAZ0noyjsBMW4ri2BaSC51pkEOkYdbepg7pJYTzfRmKORD/Z/x0NVo fNgPNgxQyWJvzrWVMiH4pIwxbP5ImSw74GZolRYAixMObZdDkR/G0of/PvjJgFdkiPoK sFJmdOJvJWSEVz67W8eoQ11LbHqIfU9m0j5k/Ozpivirw8B5bnFOkRydaBrvd+C6xgtI s+6A== X-Gm-Message-State: ALoCoQm1CHPfivTk88EX10+adqbHRdPOvHrdmdUkaxiKSok8h00orEt4TFkdEZQacuy+LaqXEBmJ X-Received: by 10.66.139.167 with SMTP id qz7mr26736080pab.23.1413978908459; Wed, 22 Oct 2014 04:55:08 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.165.144 with SMTP id o138ls522621ioe.8.gmail; Wed, 22 Oct 2014 04:55:07 -0700 (PDT) X-Received: by 10.50.4.103 with SMTP id j7mr58102igj.11.1413978907690; Wed, 22 Oct 2014 04:55:07 -0700 (PDT) X-Original-Sender: germandiago@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:14118 Archived-At: ------=_Part_3842_1606298177.1413978905985 Content-Type: text/plain; charset=UTF-8 Hello, Looking at the video from cppcon2014 from Nicolas Josuttis, he mentions about constexpr: https://www.youtube.com/watch?v=tCM4wP-dWic There are no guidelines for applying constexpr right now. There is added value in keeping the flexibility of choice about being able to use a function as constexpr. My concern is the following. If there are no rules yet, because they find it too difficult, I don't know why they don't fix the language directly with the following proposition: - Constexpr should be used only when calling a function. Functions should not be annotated with constexpr. 1. Is this technically feasible? I see some problems: constexpr functions are a subset of the language, the compiler would have to detect implementation. I don't know if this is a showstopper. I just know that D language does that. How? They allow to use a function at compile time: enum val = myNonAnnotatedWithConstexprFunc(); Maybe one problem is that you must expose potentially "constexpr" functions in header files, but once modules kick in, should this be a problem? I think there is potential value in fixing this. Thanks for your time. -- --- 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/. ------=_Part_3842_1606298177.1413978905985 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Hello, 

Looking at the video from = cppcon2014 from Nicolas Josuttis, he mentions about constexpr:
https://www.youtube.com/watch?v=3DtCM4wP-dWic

There are no guidelines for applying constexpr = right now.
There is added value in keeping the flexibility of cho= ice about being able to use a function as constexpr.

My concern is the following. If there are no rules yet, because they fin= d it too difficult,
I don't know why they don't fix the language = directly with the following proposition:

- Constex= pr should be used only when calling a function. Functions should not be ann= otated with constexpr.

1. Is this technically feas= ible? I see some problems: constexpr functions are a subset of the language= , the
compiler would have to detect implementation. I don't know = if this is a showstopper. 

I just know that D= language does that. How? They allow to use
a function at compile= time:

enum val =3D myNonAnnotatedWithConstexprFun= c();

Maybe one problem is that you must expose pot= entially "constexpr" functions in header files, but once modules
= kick in, should this be a problem?

I think there i= s potential value in fixing this. 

Thanks for= your time.

--

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To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+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/<= /a>.
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