220 2961 <02b7e63e-cd7d-4432-b3c1-fea6ecaf823e@isocpp.org> article Path: news.gmane.org!not-for-mail From: Johannes Schaub Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Improvements for string literals Date: Wed, 20 Feb 2013 15:34:33 -0800 (PST) Lines: 86 Approved: news@gmane.org Message-ID: <02b7e63e-cd7d-4432-b3c1-fea6ecaf823e@isocpp.org> References: <913f9603-aff2-4abf-a330-d4d0f8a2d1e0@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_1094_25195516.1361403273116" X-Trace: ger.gmane.org 1361403276 22715 80.91.229.3 (20 Feb 2013 23:34:36 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 20 Feb 2013 23:34:36 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCQPNCEZSQNBBCV3SWEQKGQEP5GPDBQ@isocpp.org Thu Feb 21 00:34:59 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-vb0-f70.google.com ([209.85.212.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1U8JBf-0003mT-3K for gclcip-std-proposals@m.gmane.org; Thu, 21 Feb 2013 00:34:55 +0100 Original-Received: by mail-vb0-f70.google.com with SMTP id s24sf11117154vbi.1 for ; Wed, 20 Feb 2013 15:34:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=x-received:x-beenthere:x-received:date:from:to:message-id :in-reply-to:references:subject:mime-version:x-original-sender :reply-to:precedence:mailing-list:list-id:x-google-group-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=yoJXVsuQ0TcsTJRdVDR5qti0QrKmt6/geZmmGxU0L/o=; b=xIKwJZqjFjE9I5uyKyWrZYIEIHUgvPcdj7I3KQwMsAgVQG/hkWGCrXaEk4mgr1dWiB bXzdB/aRzxR1l/ASeFIE6B0Yz5GQE//tuvS1ML2phdH8rV3cBob5QGkzQegFzaPh2se8 cblwGr9p0P/pVQNQvgKU1ICyZf+DTsWBwxaH/GmbT0VOzk6cow1Ud+ysTHB/dlw8LrzW slHO/t1+1PWuZMeLHL+KV6GV7FjCKylI1zwLLK12CI3Ys10Tmres+HwrEJTytrs6Vxkz HiZpiwVisiY84VkIEXMmOOeI3wGGOwJ7x64/6VoNSJ5QWN2t/NQH1+5YgiZ7zkBrUI3z dzQg== X-Received: by 10.236.133.242 with SMTP id q78mr11188534yhi.22.1361403274266; Wed, 20 Feb 2013 15:34:34 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.49.63.137 with SMTP id g9ls3075904qes.87.gmail; Wed, 20 Feb 2013 15:34:33 -0800 (PST) X-Received: by 10.49.4.231 with SMTP id n7mr1852207qen.34.1361403273427; Wed, 20 Feb 2013 15:34:33 -0800 (PST) In-Reply-To: <913f9603-aff2-4abf-a330-d4d0f8a2d1e0@isocpp.org> X-Original-Sender: schaub.johannes@googlemail.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:2961 Archived-At: ------=_Part_1094_25195516.1361403273116 Content-Type: text/plain; charset=ISO-8859-1 On Monday, February 11, 2013 3:52:27 AM UTC+1, Nicol Bolas wrote: > > Note: the type `charT` refers to any of the available character types, for > the various string literals. > > It is often useful to want to differentiate between a mere string and a > string that comes from a string literal. So what I was thinking was that > string literals should return some specialized type, which can be used > instead of a `const charT[]`/`const charT*`. > > I have proposed in some discussions that we could also have a type that is special cased by overload resolution similar to std::initializer_list. Where that type is special cased for "{...}", our additional type is special cased for string literals. Example: void f(string_ref s) { } void f(const char (&x)[4]) { } string_ref could be that language-support type. When you then call f with a string literal "foo", special overload resolution rules say that the first f is picked, even though the conversion sequence for both parameters would be an identity conversion (string-literal -> string_ref => identity conversion. not a user defined conversion sequence!). -- --- 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/?hl=en. ------=_Part_1094_25195516.1361403273116 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable

On Monday, February 11, 2013 3:52:27 AM UTC+1, Nicol Bolas wrote:Note: the type `charT` refers to= any of the available character types, for the various string literals.
=
It is often useful to want to differentiate between a mere string and a= string that comes from a string literal. So what I was thinking was that s= tring literals should return some specialized type, which can be used inste= ad of a `const charT[]`/`const charT*`.


=
I have proposed in some discussions that we could also have a type tha= t is special cased by overload resolution similar to std::initializer_list.= Where that type is special cased for "{...}", our additional type is speci= al cased for string literals. Example:

  &nbs= p; void f(string_ref s) {

    }

    void f(const char (&x)[4]) { }

string_ref could be that language-support type. When you th= en call f with a string literal "foo", special overload resolution rules sa= y that the first f is picked, even though the conversion sequence for both = parameters would be an identity conversion (string-literal -> string_ref= =3D> identity conversion. not a user defined conversion sequence!).

--
 
---
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-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-pro= posals/?hl=3Den.
 
 
------=_Part_1094_25195516.1361403273116-- .