220 38246 article Path: news.gmane.org!.POSTED!not-for-mail From: Nicol Bolas Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Simple, terse universal forwading for the next decade Date: Mon, 28 May 2018 12:06:08 -0700 (PDT) Lines: 87 Approved: news@gmane.org Message-ID: References: <80548757-8a42-499a-bf15-3670b2727082@isocpp.org> <8d3b34de-c06a-4083-bb0c-8e2c7482abf0@isocpp.org> <9930a9dc-b998-4431-a159-6d72d1d9b2ff@isocpp.org> <8e1c6607-a92d-496b-aad1-e992e049a748@isocpp.org> <2f782c2d-e89c-4d8b-8ef6-372c00e62ab1@isocpp.org> <93ee46a2-1469-48ae-b931-c060946f38d5@isocpp.org> <609892ba-f717-4458-b9e3-c5975378ad29@isocpp.org> <4d68237c-077a-4408-abf1-5f9670311f71@isocpp.org> <70fe7dc7-b8a6-4498-9aa6-f88e6af06506@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_22019_1239524599.1527534368794" X-Trace: blaine.gmane.org 1527534246 32338 195.159.176.226 (28 May 2018 19:04:06 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 28 May 2018 19:04:06 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCEKFTV6ZUMBBINGWHMAKGQESW6MZFY@isocpp.org Mon May 28 21:04:02 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yw0-f200.google.com ([209.85.161.200]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fNNR1-0008Gk-Cf for gclcip-std-proposals@m.gmane.org; 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Mon, 28 May 2018 12:06:10 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 2002:a81:2089:: with SMTP id g131-v6ls3174350ywg.34.gmail; Mon, 28 May 2018 12:06:09 -0700 (PDT) X-Received: by 2002:a81:9341:: with SMTP id k62-v6mr422704ywg.4.1527534369448; Mon, 28 May 2018 12:06:09 -0700 (PDT) In-Reply-To: X-Original-Sender: jmckesson@gmail.com 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:38246 Archived-At: ------=_Part_22019_1239524599.1527534368794 Content-Type: multipart/alternative; boundary="----=_Part_22020_1433131758.1527534368794" ------=_Part_22020_1433131758.1527534368794 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Monday, May 28, 2018 at 1:50:41 PM UTC-4, Ga=C5=A1per A=C5=BEman wrote: > > Also, I meant =3D> as prefix. Postfix unary operators are *weird*. > One of the problems with the prefix `>>` that was proposed in the older=20 proposal was that this was weird: `[name=3D>>arg]`. The `=3D>` prefix would= =20 have the same oddity. What I wonder about is the design space for contextual keywords. C++ has=20 only used them in two places, but right now, I don't believe `= =20 ` has a syntactic meaning in an expression. As such, it is at= =20 least theoretically possible to apply a contextual keyword `fwd` to an=20 identifier. But it would *only* work when followed by an identifier, not=20 when followed by arbitrary expressions or even `(`. Things like this are why the committee should have adopted the P0056: Soft= =20 Keywords proposal. There are just too many places in the language where a= =20 keyword is a natural solution, but selecting the "right" keyword is hard=20 and/or the problem isn't worth the cost of a true keyword. --=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/f98f4f3a-18e3-464f-a299-be18b9c20439%40isocpp.or= g. ------=_Part_22020_1433131758.1527534368794 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Monday, May 28, 2018 at 1:50:41 PM UTC-4, Ga=C5=A1per A= =C5=BEman wrote:
Also, I meant =3D> as prefix. Postfix unary operators= are *weird*.

One of the proble= ms with the prefix `>>` that was proposed in the older proposal was t= hat this was weird: `[name=3D>>arg]`. The `=3D>` prefix would have= the same oddity.

What I wonder about is the desig= n space for contextual keywords. C++ has only used them in two places, but = right now, I don't believe `<identifier> <identifier>` has = a syntactic meaning in an expression. As such, it is at least theoretically= possible to apply a contextual keyword `fwd` to an identifier. But it woul= d only work when followed by an identifier, not when followed by arb= itrary expressions or even `(`.

Things like this a= re why the committee should have adopted the P0056: Soft Keywords proposal.= There are just too many places in the language where a keyword is a natura= l solution, but selecting the "right" keyword is hard and/or the = problem isn't worth the cost of a true keyword.

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To view this discussion on the web visit https://groups.google.= com/a/isocpp.org/d/msgid/std-proposals/f98f4f3a-18e3-464f-a299-be18b9c20439= %40isocpp.org.
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