220 30209 <8e7586fb-a121-4045-8f1e-a1399e229521@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: Nicol Bolas Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: enum_cast proposal Date: Tue, 3 Jan 2017 19:43:33 -0800 (PST) Lines: 96 Approved: news@gmane.org Message-ID: <8e7586fb-a121-4045-8f1e-a1399e229521@isocpp.org> References: <2225413.PkzHcSPZVx@tjmaciei-mobl1> <7d89ec43-c691-44d8-bcb5-74dcda9eb493@isocpp.org> <6951935.9LYeBEmE6C@tjmaciei-mobl1> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_2648_1779129782.1483501413787" X-Trace: blaine.gmane.org 1483501422 7097 195.159.176.226 (4 Jan 2017 03:43:42 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 4 Jan 2017 03:43:42 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCEKFTV6ZUMBBZW6WHBQKGQEEPOMCAA@isocpp.org Wed Jan 04 04:43:38 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pg0-f72.google.com ([74.125.83.72]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cOcUC-0000Ky-FV for gclcip-std-proposals@m.gmane.org; Wed, 04 Jan 2017 04:43:36 +0100 Original-Received: by mail-pg0-f72.google.com with SMTP id u5sf944596156pgi.7 for ; Tue, 03 Jan 2017 19:43:35 -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=YhmvZKVZdxdHWIFAAulzoQdDh3Im4whH7V2v44U4ukU=; b=kGo7GEhGby15I6CUvcMnBTHAKDBRSetsjQJVntWrUBIyUPgW6hrheTBIw3IZSsEwuu lRgm4sk/r2kljEEbMecG/Kesfw/cdH1LDpINMdIhc3tY4AqG5jUHibT9aZBwNx+mc/TQ PlZJgj9qt6koC4FPO9jPl1P0f/I7aGF/9DfM0vKxXWfm6dDvGi6fTUfZvj7XqjMGYmUF n0YijhP9ydktEvVGlLBXZLa5eVbIpi6fYtmT9mObfjcpvQnZH35CSSTb7gN2smQlR1pa io6WO3uXwhbIaAavK/pOFuXFBK/L0ux2uLdS+m9vVsCxa05VbnjkSdSMzWXK0tHlZ11E vydQ== 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=YhmvZKVZdxdHWIFAAulzoQdDh3Im4whH7V2v44U4ukU=; b=BrF74Pb3GpxtP81b/opIYjxQ4mOrrwYxYVs2EbovsCYlpI45j3IpeNN4lM5EOtHwFv eIomhZI26BDXRAt294Jy0bGcR2PQ9Y4nwEsyEJUd70JQoc3alO998RG70sWSLhl1vbNY jVflGX6ejJoMF02uueAmZkhSQaPDjnH2JivPGeuR/AZwW/fMdiV2vUJLEGi+xhyzqu+a 0Vk6r3+Gz6VIocFoLHHld+kERq+bW0Os031/IVc9onZtTPZdu6TDatCrR582gaOj64K2 h3HfAzVfbvFLdmZY8atlqa4fqpOA2EsQoU3Mw+vEYVByP8MHgvwsgF4ZJ+U+pDj4s5ok VeCg== 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=YhmvZKVZdxdHWIFAAulzoQdDh3Im4whH7V2v44U4ukU=; b=LT2N/5XdHDB6Q/aXH96V0xElxT8m6rCvZdpuy9NfCxFJklE5hOOwMuCrvOn14k/Ytf cUK+/vXod1pIqdj28kYF0GTz/pj7QFNJtxqJfg8QSDsDQFlPHxB4JnmHADqdfsTaZ8em 9zKCflFIn/0D0EHjmAfcfVCTHHLCnEFfElq2KyMRgbxB55sLuZ48XUO8qq1mBwoOd6LD JmSeOILfy/wB726s0MJwsI1lrwiKqP5VvdmXn4L4yliWGCDdK07cbo+smmiN0yJEMWfw ++wbRub5A8EpcJ3afmFhfauHSI9d0J99GiaaMLWmJG1yhBSan5Z0rPU0rGFxpS3qvfyQ J7eg== X-Gm-Message-State: AIkVDXLH61xNOFZYNoQWruaTgo+JEDihTs5xJMzMYICw5nhoDUYXpDArNKS5df4UJnLNww== X-Received: by 10.99.146.2 with SMTP id o2mr37787298pgd.173.1483501415069; Tue, 03 Jan 2017 19:43:35 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.21.124 with SMTP id z57ls21262870otz.38.gmail; Tue, 03 Jan 2017 19:43:34 -0800 (PST) X-Received: by 10.157.18.211 with SMTP id g77mr3012428otg.14.1483501414358; Tue, 03 Jan 2017 19:43:34 -0800 (PST) In-Reply-To: <6951935.9LYeBEmE6C@tjmaciei-mobl1> X-Original-Sender: jmckesson@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:30209 Archived-At: ------=_Part_2648_1779129782.1483501413787 Content-Type: multipart/alternative; boundary="----=_Part_2649_1755174923.1483501413787" ------=_Part_2649_1755174923.1483501413787 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Tuesday, January 3, 2017 at 6:15:02 PM UTC-5, Thiago Macieira wrote: > > On ter=C3=A7a-feira, 3 de janeiro de 2017 11:59:46 BRST Nicol Bolas wrote= :=20 > > Lastly, having `enum_cast` work via some compiler-defined type is rathe= r=20 > > extreme for something as simplistic as this, don't you think? There are= =20 > > only so many ways to implement an "optional", and you can define=20 > implicit=20 > > conversions from `std::optional` type to yours with little penalty. The= =20 > > conversion can even be `constexpr`, just like `std::optional`, so you= =20 > would=20 > > suffer no loss of performance in constexpr contexts.=20 > > Anything that is a compiler feature (a builtin or a core language=20 > expression)=20 > needs to be able to choose between std::optional,=20 > std::experimental::optional=20 > and std::__1::optional by just changing #includes. > .... why? std::experimental::optional isn't part of the standard. And I have= =20 no idea what `std::__1::optional` is. --=20 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 e= mail 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/8e7586fb-a121-4045-8f1e-a1399e229521%40isocpp.or= g. ------=_Part_2649_1755174923.1483501413787 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Tuesday, January 3, 2017 at 6:15:02 PM UTC-5, T= hiago Macieira wrote:
On ter=C3= =A7a-feira, 3 de janeiro de 2017 11:59:46 BRST Nicol Bolas wrote:
> Lastly, having `enum_cast` work via some compiler-defined type is = rather
> extreme for something as simplistic as this, don't you think? = There are
> only so many ways to implement an "optional", and you ca= n define implicit
> conversions from `std::optional` type to yours with little penalty= .. The
> conversion can even be `constexpr`, just like `std::optional`, so = you would
> suffer no loss of performance in constexpr contexts.

Anything that is a compiler feature (a builtin or a core language expre= ssion)=20
needs to be able to choose between std::optional, std::experimental::op= tional=20
and std::__1::optional by just changing #includes.

... why? std::experimental::optional isn't part of the standard. A= nd I have no idea what `std::__1::optional` is.

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
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.
To view this discussion on the web visit https://groups.google.= com/a/isocpp.org/d/msgid/std-proposals/8e7586fb-a121-4045-8f1e-a1399e229521= %40isocpp.org.
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