220 2905 <511FFA5B.7050204@wanadoo.fr> article Path: news.gmane.org!not-for-mail From: "Vicente J. Botet Escriba" Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: std::optional -- request for feedback on the wording Date: Sat, 16 Feb 2013 22:30:03 +0100 Lines: 221 Approved: news@gmane.org Message-ID: <511FFA5B.7050204@wanadoo.fr> References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="------------010209000306010006010405" X-Trace: ger.gmane.org 1361050205 12340 80.91.229.3 (16 Feb 2013 21:30:05 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 16 Feb 2013 21:30:05 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDH67CONY4PBBXXU76EAKGQEZ4GQ3HY@isocpp.org Sat Feb 16 22:30:27 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wi0-f197.google.com ([209.85.212.197]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1U6pL0-0001Xk-5S for gclcip-std-proposals@m.gmane.org; Sat, 16 Feb 2013 22:30:26 +0100 Original-Received: by mail-wi0-f197.google.com with SMTP id hn17sf2733351wib.4 for ; Sat, 16 Feb 2013 13:30:06 -0800 (PST) X-Received: by 10.180.75.8 with SMTP id y8mr1898364wiv.1.1361050206186; Sat, 16 Feb 2013 13:30:06 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.181.13.74 with SMTP id ew10ls274552wid.52.gmail; Sat, 16 Feb 2013 13:30:05 -0800 (PST) X-Received: by 10.14.3.133 with SMTP id 5mr24448154eeh.43.1361050205477; Sat, 16 Feb 2013 13:30:05 -0800 (PST) X-Received: by 10.14.3.133 with SMTP id 5mr24448141eeh.43.1361050205432; Sat, 16 Feb 2013 13:30:05 -0800 (PST) Original-Received: from smtp.smtpout.orange.fr (smtp09.smtpout.orange.fr. [80.12.242.131]) by mx.google.com with ESMTP id r44si23777547eeo.41.2013.02.16.13.30.05; Sat, 16 Feb 2013 13:30:05 -0800 (PST) Received-SPF: neutral (google.com: 80.12.242.131 is neither permitted nor denied by best guess record for domain of vicente.botet@wanadoo.fr) client-ip=80.12.242.131; Original-Received: from iMac-de-Vicente-Botet-Escriba.local ([2.11.125.164]) by mwinf5d69 with ME id 19W41l0093YwBk2039W4S9; Sat, 16 Feb 2013 22:30:05 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:17.0) Gecko/20130107 Thunderbird/17.0.2 In-Reply-To: X-Original-Sender: vicente.botet@wanadoo.fr X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 80.12.242.131 is neither permitted nor denied by best guess record for domain of vicente.botet@wanadoo.fr) smtp.mail=vicente.botet@wanadoo.fr 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:2905 Archived-At: This is a multi-part message in MIME format. --------------010209000306010006010405 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Le 15/02/13 14:46, Andrzej Krzemien'ski a =E9crit : > Hi everyone, > We have updated the proposal based on recent feedback. I enclose the=20 > latest draft. It is also available at: > http://kojot.sggw.waw.pl/~akrzemi1/optional/tr2.optional.proposal.html=20 > > > We would appreciate your feedback, especially on the standardese. > > Hi, Next follows some remarks * As optional references are part of the auxiliary proposal, shouldn't=20 the following be removed from 20.5.1? An /optional object for lvalue reference types/ is an object capable of=20 storing the address of another object. The address stored by the=20 optional object can be changed or set to a value that does not represent=20 a valid address. |* optional::optional(const optional& rhs);| What about adding a post-condition on the copied value |false =3D=3D bool(rhs)| || rhs.value() =3D=3D this->value() What about adding noexecpt |optional::optional(const optional& rhs) noecept(see below); | ||Remarks:||The expression inside |noexcept| is equivalent to:| is_nothrow_copy_constructible::value | |* optional::optional(const T& v); | |I'm curious to know How the remark can be implemented in C++11 | ||Remarks:||If |T|'s selected constructor is a |constexpr| constructor,=20 this constructor shall be a |constexpr| constructor. What about adding a post-condition on the copied value v =3D=3D this->value() What about noexcept(is_nothrow_copy_constructible::value||) as before? | * There is an assignment from U, but not a constructor from U. Is this=20 missing? ||| |* template constexpr bool operator=3D=3D(const optional& x,= =20 const optional& y); I don't understand the remark | Instantiations of this function template for which |*x =3D=3D *y| is a core constant expression, shall be |constexpr| functions. |Is the function a constexpr or not? Best, Vicente | --=20 ---=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. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposa= ls/?hl=3Den. --------------010209000306010006010405 Content-Type: text/html; charset=ISO-8859-1
Le 15/02/13 14:46, Andrzej Krzemieński a écrit :
Hi everyone,
We have updated the proposal based on recent feedback. I enclose the latest draft. It is also available at:
http://kojot.sggw.waw.pl/~akrzemi1/optional/tr2.optional.proposal.html

We would appreciate your feedback, especially on the standardese.


Hi,

Next follows some remarks

* As optional references are part of the auxiliary proposal, shouldn't the following be removed from 20.5.1?

An optional object for lvalue reference types is an object capable of storing the address of another object. The address stored by the optional object can be changed or set to a value that does not represent a valid address.

* optional<T>::optional(const optional<T>& rhs);

What about adding a post-condition on the copied value
false == bool(rhs) || rhs.value() == this->value()

What about adding noexecpt
optional<T>::optional(const optional<T>& rhs) noecept(see below);

Remarks: The expression inside noexcept is equivalent to: 
is_nothrow_copy_constructible<T>::value

* optional<T>::optional(const T& v);

I'm curious to know How the remark can be implemented in C++11

Remarks: If T's selected constructor is a constexpr constructor, this constructor shall be a constexpr constructor.

What about adding a post-condition on the copied value
v == this->value()

What about noexcept(is_nothrow_copy_constructible<T>::value) as before?


* There is an assignment from U, but not a constructor from U. Is this missing?


* template <class T> constexpr bool operator==(const optional<T>& x, const optional<T>& y);


I don't understand the remark

Instantiations of this function template for which *x == *y is a core constant expression, shall be constexpr functions.

Is the function a constexpr or not?

Best,
Vicente

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