220 39504 article Path: news.gmane.org!.POSTED!not-for-mail From: "'Hamza Sood' via ISO C++ Standard - Future Proposals" Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Contract attributes and trailing return types Date: Thu, 2 Aug 2018 11:51:24 -0700 (PDT) Lines: 118 Approved: news@gmane.org Message-ID: References: <08e4fce4-e6c6-4dc2-a9ca-098f1ed8b380@isocpp.org> <9dd24044-8886-4b01-8724-0586b5ed1f55@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_373_1589672321.1533235884673" X-Trace: blaine.gmane.org 1533235761 7107 195.159.176.226 (2 Aug 2018 18:49:21 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 2 Aug 2018 18:49:21 +0000 (UTC) Cc: hamza_sood@me.com To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCP5NIM2SYKRBLNFRXNQKGQE5MKBXZY@isocpp.org Thu Aug 02 20:49:17 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yb0-f199.google.com ([209.85.213.199]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1flIey-0001iz-0t for gclcip-std-proposals@m.gmane.org; Thu, 02 Aug 2018 20:49:16 +0200 Original-Received: by mail-yb0-f199.google.com with SMTP id w13-v6sf1854020ybk.5 for ; Thu, 02 Aug 2018 11:51:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:x-original-sender:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe; bh=DSpC02TT7Mx7V5Rzk92UXHL04cN5WfoKwEB7tM3EV8E=; b=ijqSF/Gwg4AwnPD/23/MQN4qcQZGAaatibGgRQzT9yETfm2DJIVFqHubh+nL46WIvW eiueP0YJcThNssaBUBA0pBhNfcLhERQS8M7e+sifhzwfxKEimj2qeL/mHtRFfD0gUs7i K2uYUcHObbW7BA83LBQAkzx7nNAoUTicTUGAP/LHc/dAbmVZHIrrUl1s/7ctqQyX+z6m N6GIuPHb8RZm7f2F6EddZsiwhgGfUiMmbY8J51MmSg6DZ5lbI7bFWA9jFx4NQgN64F7w r8brTKmAiP7baDKvotp4cFqeVZv12jfcuv+8yQtooN5BfGbDxUbgldXMZW6b5uz3gQRn CYag== 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:cc: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=DSpC02TT7Mx7V5Rzk92UXHL04cN5WfoKwEB7tM3EV8E=; b=SFcQVtc8cVfjbk4mu0WgbOrVS94e3425srA370cQ70qraxBrcV4ZtwhMJkf/dhS3i/ FBu8mUJZmpRoz4JWmWGNREloSKX1QexpsMO+MOuvSW6sbcsx9IsYqsNCMjZcdcJFp/Qt 4VB6BSVDf+vVYelL3GExgUa3wOJpwVal03TIztAV9/G1GsxFzCpwZW/cWrOBqWmHvK9o qi+yb+GC1CI9A+WEVs2fUg2RX6ASerKgWNGUIdmn99Kzihu24XwXUupwiJncdNK0T1dH 3YlRhiRFl9a9zmZPgbADgKFd5CK6sg90qg+pbvBHZe6/I9pAYXuT0Q77f0TBY6dOU3ao hQIQ== X-Gm-Message-State: AOUpUlHi1AQjmjFoWXwC5BdNplV/+U5SzBojDhqLZbZ4wDc/SarJEaWN BDzii9LfkKGCrQefVS5pL5XRFg== X-Google-Smtp-Source: AAOMgpdM6j7O9yDPcrRYJXQwsLj0CZ0eQGdybQsasuexkROk3CFcVzvtY0111/SSinHN0s4sGTxLRQ== X-Received: by 2002:a5b:3cf:: with SMTP id t15-v6mr992192ybp.10.1533235886552; Thu, 02 Aug 2018 11:51:26 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 2002:a0d:d414:: with SMTP id w20-v6ls528843ywd.13.gmail; Thu, 02 Aug 2018 11:51:25 -0700 (PDT) X-Received: by 2002:a0d:de01:: with SMTP id h1-v6mr97308ywe.3.1533235885148; Thu, 02 Aug 2018 11:51:25 -0700 (PDT) In-Reply-To: <9dd24044-8886-4b01-8724-0586b5ed1f55@isocpp.org> X-Original-Sender: hamza_sood@me.com X-Original-From: Hamza Sood Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org 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:39504 Archived-At: ------=_Part_373_1589672321.1533235884673 Content-Type: multipart/alternative; boundary="----=_Part_374_99762319.1533235884673" ------=_Part_374_99762319.1533235884673 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Right, but the current placement also conflicts with an existing meaning:= =20 attributes at that location appertain to the function type. On Wednesday, August 1, 2018 at 11:16:47 PM UTC+1, T. C. wrote: > > When there's no requires-clause, an attribute at that location already ha= s=20 > a meaning: it appertains to some portion of the return type. For example: > > auto f() -> int [[meow]]; // [[meow]] is part of the type-specifier-seq;= =20 > appertains to the type "int". > auto y() -> int(*)() [[purr]]; // [[purr]] appertains to the type int(). > > On Tuesday, July 31, 2018 at 3:08:40 PM UTC-4, Hamza Sood wrote: >> >> Would anything break if a dedicated contract-specifier-seq was added=20 >> after the requires-clause? >> >> It feels really messy having contracts interrupt the function type like= =20 >> that, especially when they don=E2=80=99t really have anything to do with= it=20 >> (semantically anyway). >> >> On Friday, July 27, 2018 at 4:59:24 AM UTC+1, Nicol Bolas wrote: >>> >>> On Thursday, July 26, 2018 at 9:07:47 PM UTC-4, Tony V E wrote: >>>> >>>> How does this compare to where `requires` goes? Is that before or=20 >>>> after the trailing return? >>>> >>> >>> It appears to be after the whole thing, including the trailing return.= =20 >>> It seems to be: >>> >>> Identifier/auto function_name(...) cv_qualifiers &/&& noexcept=20 >>> attributes trailing-return-type requires-clause >>> >>> C++'s syntax is a huge mess... >>> >> --=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/c46dda85-6994-464b-b505-0a712ce51cb4%40isocpp.or= g. ------=_Part_374_99762319.1533235884673 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Right, but the current placement also conflicts with an ex= isting meaning: attributes at that location appertain to the function type.=

On Wednesday, August 1, 2018 at 11:16:47 PM UTC+1, T. C. wrote:
When there's = no requires-clause, an attribute at that location already has a meaning: it= appertains to some portion of the return type. For example:

<= /div>
auto f() -> int [[meow]];=C2=A0 // [[meow]] is part of the typ= e-specifier-seq; appertains to the type "int".
auto y()= -> int(*)() [[purr]]; // [[purr]] appertains to the type int().

On Tuesday, July 31, 2018 at 3:08:40 PM UTC-4, Hamza= Sood wrote:
W= ould anything break if a dedicated contract-specifier-seq was added after t= he requires-clause?

It feels really messy having c= ontracts interrupt the function type like that, especially when they don=E2= =80=99t really have anything to do with it (semantically anyway).

= On Friday, July 27, 2018 at 4:59:24 AM UTC+1, Nicol Bolas wrote:
On Thursday, July 26, 2018 at= 9:07:47 PM UTC-4, Tony V E wrote:
How does this compare to where `requires` goes?=C2= =A0 Is that before or after the trailing return?

It appears to be after the whole thing, including the= trailing return. It seems to be:

Identifier/auto = function_name(...) cv_qualifiers &/&& noexcept attributes trail= ing-return-type requires-clause

C++'s syntax i= s a huge mess...

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