220 32371 <3657aeea-1787-40ee-9320-9b6e6466f061@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: Nicol Bolas Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: When C++ will support unconstrained generic functions ? Date: Tue, 9 May 2017 11:30:47 -0700 (PDT) Lines: 104 Approved: news@gmane.org Message-ID: <3657aeea-1787-40ee-9320-9b6e6466f061@isocpp.org> References: <2b6b016d-3463-416b-afd5-d10bac62a334@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_3672_28380956.1494354647618" X-Trace: blaine.gmane.org 1494354648 20721 195.159.176.226 (9 May 2017 18:30:48 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 9 May 2017 18:30:48 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCEKFTV6ZUMBBWEVZDEAKGQE43WD2UA@isocpp.org Tue May 09 20:30:44 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pg0-f69.google.com ([74.125.83.69]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1d89uF-0005IM-MI for gclcip-std-proposals@m.gmane.org; Tue, 09 May 2017 20:30:43 +0200 Original-Received: by mail-pg0-f69.google.com with SMTP id q125sf6114135pgq.8 for ; Tue, 09 May 2017 11:30:49 -0700 (PDT) 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=aMIx2KIiIP0qrQfgHA1HUc4vZ5Eioupyxpr9dQcCxFw=; b=GYkhl45ZCSE2xEDDFa2Q2I3OmtR4FbQAU/rZMqgtfBsL60HkNlUi0bi+LABtpOVmsl Aw/Sx4On4DVATCxN89mjykvXgzf8Pyj2RtpffX0FmWIB+LzdvuXobQsc8jD8UGrrxuCC 3OhGwh3MsiVjwDQ01hlo++/zvKCymVzbVR34GBbweg5VO0OZByYO3C9djQGAX/ug6Umy BV1Pj7grJPUvvzG5Ju/HoEGJ9OyCZRsSud0BLvt0JL+AzC4gmGIuBzwYOfVFlWoct+za LV6tHBwFBvAKSF9jQFASsVaKrcl2BSaMtj0Z89ImHd3zj2J5IMR7KjfBFbMJ9w24dQgY zi4g== 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=aMIx2KIiIP0qrQfgHA1HUc4vZ5Eioupyxpr9dQcCxFw=; b=aRa52HPAtEfNvkg1RkXRICRTeB+NvcRfnlTEtQwsNkbmdmHIRXjBiAfOLK7DsEUod0 MgYIfYdlqJmmQ+T7q2ligF4PpRAkioLT0riReXqCFkShjIsXgu0PiQRO9iJld1kOJbgg zFKLuGOqKg1H1x9Qa3G4Es8S1FYhsemc84ii3o4Kp4lF6C5uHTwk4KrMgBHzgWWZgV8Z M1ENqZpV5kTKhx2PiFvWILQRuYxTHgSBNEuYzFqQsL7sdqiLPFdaZHOqRdr83QcH2Z78 Cu9l9yTGY/cJ/NUdbR99PuElPEskzrKQWsXXfHGODhynlcif4Dyetichyn+LluOuOJdn 3l9Q== 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=aMIx2KIiIP0qrQfgHA1HUc4vZ5Eioupyxpr9dQcCxFw=; b=H9UZg/EIJMGpUPwQbqF5eXSWpga+CYwPBAGB8mIb2zBcvvWRZlmSYv0SZ2t5LK8obp WwB+W2db6765sruwmtZYz0R+SZW/skmJyocHMYOVPYBuG9IO1IU+pZL2H2F0oB4XOlBX vWIyDIkXPPjZhid3mqU6zxIWCZN6SP2xXJ2nvfsgsqITP/CEhZP2FQScwloNtzkJMSUA +t1oGIPYIVNDVmhrZmMqiagTPgVQHg+A3T7aG3+ZWuBnEu3tFXZf1iJr+Vk8/ya5S5bL aV6lC+w75tz4edvtEUiG5c3UWIIIcJ/p8OnDreDzP6vgNOs1ggbcwv09kPLfViJXLfDR rsrg== X-Gm-Message-State: AODbwcAULAHfnHGrTTQJvDg4aK08xeHijfTqdxepTV3EOwCNgr708k/0 4eGeeIDs5/sz4w== X-Received: by 10.98.18.81 with SMTP id a78mr654603pfj.23.1494354648929; Tue, 09 May 2017 11:30:48 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.11.144 with SMTP id 16ls910526oth.36.gmail; Tue, 09 May 2017 11:30:48 -0700 (PDT) X-Received: by 10.157.37.213 with SMTP id q79mr31123ota.11.1494354648128; Tue, 09 May 2017 11:30:48 -0700 (PDT) In-Reply-To: <2b6b016d-3463-416b-afd5-d10bac62a334@isocpp.org> 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:32371 Archived-At: ------=_Part_3672_28380956.1494354647618 Content-Type: multipart/alternative; boundary="----=_Part_3673_61053338.1494354647618" ------=_Part_3673_61053338.1494354647618 Content-Type: text/plain; charset="UTF-8" On Tuesday, May 9, 2017 at 2:17:45 PM UTC-4, Denis Kotov wrote: > > Hi Nicol, > > It is very strange why it is a part of concept, for me it seems like > extension for templates > Because the Concepts TS defines the ability to constraint function parameters transparently: void Func(ConceptName t); is equivalent to: template void Func(T t); `auto` is thus redefined as simply an unconstrained context. It's not strange at all. It's a natural thing for Concepts TS to do. And besides, once you have concepts, you'll be using them far more than `auto` for function parameters. There aren't that many functions that can truly take *any* type. Even forwarding functions like `emplace` should constrain their parameters to those types which can actually be used to construct the object they're supposed to. -- 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. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/3657aeea-1787-40ee-9320-9b6e6466f061%40isocpp.org. ------=_Part_3673_61053338.1494354647618 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Tuesday, May 9, 2017 at 2:17:45 PM UTC-4, Denis Kotov w= rote:
Hi Nicol= ,

It is very strange why it is a part of concept, for me it seems li= ke extension for templates

Because the Concepts = TS defines the ability to constraint function parameters transparently:
=
void= Func(ConceptName t);

is equiva= lent to:

template<= ConceptName T>
void Func(T t);

`auto` is thus redefined as si= mply an unconstrained context.

It's not strange at all. It's= a natural thing for Concepts TS to do. And besides, once you have concepts= , you'll be using them far more than `auto` for function parameters. Th= ere aren't that many functions that can truly take any type. Eve= n forwarding functions like `emplace` should constrain their parameters to = those types which can actually be used to construct the object they're = supposed to.

--
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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/3657aeea-1787-40ee-9320-9b6e6466f061= %40isocpp.org.
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