220 21845 <0ebbe01b-854b-4b72-be74-a8dff8785d1c@isocpp.org> article Path: news.gmane.org!not-for-mail From: Gor Nishanov Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: is await an extension of the do-notation? (was Re: Re: Resumable expressions p0114r0 vs async/await P0057R0) Date: Sat, 17 Oct 2015 08:41:18 -0700 (PDT) Lines: 94 Approved: news@gmane.org Message-ID: <0ebbe01b-854b-4b72-be74-a8dff8785d1c@isocpp.org> References: <639f0012-8cb4-4db3-82a6-8d042a3497f9@isocpp.org> <1d15dbc4-e0c1-4df1-86db-014e11f14d26@isocpp.org> <56114953.4030701@wanadoo.fr> <561B403D.4030403@gmail.com> <561C07D1.3080304@gmail.com> <561C213F.1060009@gmail.com> <561C3875.2050701@gmail.com> <86924069-44d0-447f-bf8a-a42e46579832@isocpp.org> <561D79A7.8080007@gmail.com> <894616d6-9609-4038-b2bc-d2c62df21e0f@isocpp.org> <99bdb3ae-9214-4440-8572-4c47a61eda46@isocpp.org> <58628096-14ae-42b2-89d3-c0bd2183bbc0@isocpp.org> <561DC957.8080603@gmail.com> <510ce172-976a-4e3a-ae68-31fdb40af4d7@isocpp.org> <9dd3f28c-4ffb-4e08-9955-242c46e14527@isocpp.org> <31d5f64f-8db9-4ba3-aca7-872114b9776d@isocpp.org> <561DE488.3040103@gmail.com> <5587a3fd-499c-42b3-bf05-fd5cdc2d9118@isocpp.org> <561EF19E.6010405@gmail.com> <7560dfa8-c77f-41ec-9c0d-c88fe65e20b5@isocpp.org> <97537282-c96c-474d-a157-9d160733cb77@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_705_210623653.1445096478452" X-Trace: ger.gmane.org 1445096488 30576 80.91.229.3 (17 Oct 2015 15:41:28 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 17 Oct 2015 15:41:28 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBC47RF4IW4GRBH6YRGYQKGQEQOTTLZI@isocpp.org Sat Oct 17 17:41:23 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qk0-f200.google.com ([209.85.220.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZnTbl-0006gQ-Kl for gclcip-std-proposals@m.gmane.org; Sat, 17 Oct 2015 17:41:21 +0200 Original-Received: by qkas79 with SMTP id s79sf122480011qka.3 for ; Sat, 17 Oct 2015 08:41:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :content-type: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=YKt+V5DIS8QHxtUI3abZm/+Zot+r94Oi80bpNKtmNVs=; b=gp+xDobPh7fIMoURO1ZlILNypeADLPLrb+L6zKeYVCxgDEPI5MEfNjnJg5DINvGLr4 lae+tD68ilLSU/EZ+upumxb5IjqAX5BzyK7hX0onTH1S3EDkHySBC139wIpIw56QEOqQ KsO6DYXvwFoEC8LUs77igDgBRttUCmo39ETE0VZVxElNBlxmdvMsC9VwlqChGuoYbudG gQq5rbysyRDEnELL80+JNLhJ8oBxF+xMdbpW5RCuvAr3KXhefB8np4KtUXwY6Cv2xlDI Tr0QPHk2cj+XjElnRnO9wYk4SHiuCSTGIoujPljYKoemnW3AAHKirP79gxdefh2eWr1Y 0lAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:message-id:in-reply-to:references :subject:mime-version:content-type: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=YKt+V5DIS8QHxtUI3abZm/+Zot+r94Oi80bpNKtmNVs=; b=FT+6fcNX8ryP597V+NXjTsHbwINFnKBoTahNxFPb/8wZhKrAhV/FnS+S/uu29TIys8 pYetblOE950x7nseUmPnaE1jvPZ1rJHaUz4E19ONZmOaxJN5iNheFVkhsfkboxe7sloT SsWszDSzxL6S7dt3jvoPhMoBLc8S+dSN5cem/AVk1g+ykuy2lZ8uTlIRaKX02p3W7rJE Hric2K8X6DhDEtgGkyAvE/oBvv/SdfmW1pBZseiLIOXY7sIr7xMIfAn6cDrBQstvf3Np 2oeAy/7W1/1BpFMUNEi6gwZ9Cxsu3dmiDCQ6MBdSeT3x1Enc5uVeWx7N63eKKIN75bbz 15Sg== X-Gm-Message-State: ALoCoQkrOjv5uR51O8L3Gpkc4s9dLiosWqRJZGjdloqhPxMn28xUuRxb5+YGMKyE70TgmsiDwxNy X-Received: by 10.140.202.202 with SMTP id x193mr9791398qha.12.1445096480529; Sat, 17 Oct 2015 08:41:20 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.117.97 with SMTP id kd1ls507865igb.19.gmail; Sat, 17 Oct 2015 08:41:19 -0700 (PDT) X-Received: by 10.50.61.132 with SMTP id p4mr233894igr.1.1445096479310; Sat, 17 Oct 2015 08:41:19 -0700 (PDT) In-Reply-To: X-Original-Sender: GorNishanov@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:21845 Archived-At: ------=_Part_705_210623653.1445096478452 Content-Type: multipart/alternative; boundary="----=_Part_706_802847780.1445096478453" ------=_Part_706_802847780.1445096478453 Content-Type: text/plain; charset=UTF-8 On Saturday, October 17, 2015 at 8:19:53 AM UTC-7, Nicol Bolas wrote: I think the real problem is that P0057 is *not meant* to be used for > generators. It *can* be, but this functionality is essentially bolted on > after-the-fact. > Indeed, for P0057 the staring point was Haskell do-notation and its C# less generic variant 'await'. Starting point for P0114 was a generator. Nevertheless, P0057 generators are at least as efficient as P0114. If you have a counter-example, please provide one. * P0114 is for lightweight generators. > Do you have an example where P0114 will result in more efficient generator than P0057? BTW, In Kona, we may get a wording to make heap elision mandatory for some common scenarios, thus, you will be guaranteed that efficiency, not just hope for it. * P0099 is for heavyweight generators (and other things), where having a > real callstack is an undeniable *need* for the problem domain. > I am a supporter of P0099 and encouraged Oliver and Nat to work on getting fibers in the library when we had discussions on it a year ago. There are definitely cases where using fibers built on top of P0099 is more appropriate than using coroutines of P0057. -- --- 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/. ------=_Part_706_802847780.1445096478453 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Saturday, October 17, 2015 at 8:19:53 AM UTC-7, Nicol B= olas wrote:

I thi= nk the real problem is that P0057 is not meant to be used for genera= tors. It can be, but this functionality is essentially bolted on aft= er-the-fact.

Indeed, for P0057 the s= taring point was Haskell do-notation and its C# less generic variant 'a= wait'. Starting point for P0114 was a generator.
Nevertheless= , P0057 generators are at least as efficient as P0114. If you have a counte= r-example, please provide one.

* P0114 is for lightweight generators.

Do you have an example where P0114 will result= in more efficient generator than P0057?
BTW, In Kona, we may get= a wording to make heap elision mandatory for some common scenarios, thus, = you will be guaranteed that efficiency, not just hope for it.
* P0099 is for hea= vyweight generators (and other things), where having a real callstack is an= undeniable need for the problem domain.
=
I am a supporter of P0099 and encouraged Oliver and Nat to w= ork on getting fibers in the library when we had discussions on it a year a= go.
There are definitely cases where using fibers built on top of= P0099 is more appropriate than using coroutines of P0057.

--

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