220 38455 <48f336e3-146b-4317-8a60-1a3acc16af4b@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: Nicol Bolas Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Concepts fragmentation problem Date: Sat, 2 Jun 2018 18:59:34 -0700 (PDT) Lines: 76 Approved: news@gmane.org Message-ID: <48f336e3-146b-4317-8a60-1a3acc16af4b@isocpp.org> References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_19391_1506462426.1527991174651" X-Trace: blaine.gmane.org 1527991051 15627 195.159.176.226 (3 Jun 2018 01:57:31 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 3 Jun 2018 01:57:31 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCEKFTV6ZUMBBB4XZXMAKGQE2EMRHII@isocpp.org Sun Jun 03 03:57:26 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yb0-f200.google.com ([209.85.213.200]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fPIGr-0003wQ-O4 for gclcip-std-proposals@m.gmane.org; Sun, 03 Jun 2018 03:57:25 +0200 Original-Received: by mail-yb0-f200.google.com with SMTP id h29-v6sf1326350ybj.22 for ; Sat, 02 Jun 2018 18:59:36 -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 :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=mynFxL12SQF4lSRhsJTtRSX2OewF4sD0aLaXOzgVxS4=; b=X9QRxAfZfxry1yluyYSpLIJqy35CryHU2YMK1zJYx0om7OYyqrpEQuB1ImfDSbKqGj /BT5OqTQT+tizC61+1zjrsIkT5uUk96Rbqh2bnUYuCfXP/TYC1bnHGWG9uumOTeuu7hx STYlKfJ7Ap3UfIJwjFJ/56O7qQUT9Q3K/2dHnkyRAyvwhCG5nHLnumvVenAzZMZlImF/ MN50+5Efpk92Z+Mv1w5wZt/r3FBYmr3GyYnRaLXPXMW6zdWtvqW7bCnYTMfku30EJLma JURjgek8XzfcgSq/1HiNh42YCc2rHBW0WL/QVvUmAx+2aYQ9ZF6uDh0eNulQbxa7h+J/ eR5Q== 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 :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=mynFxL12SQF4lSRhsJTtRSX2OewF4sD0aLaXOzgVxS4=; b=s3p3N1jVnAYXgnOgUF4ZPnhYJ+7mMut8XAifejscPXDfTgL4lj/oJ1CD1NgmXYoKcs WSMm9/wBtxKt5vC2UmdndFlarp4gYqmQQt/AYWZE/CAaigYSUiDE6w3YD8VjYvV3fHnu AGlHyF87eDjzYr4TrKMi4OIiRPtk1g0K2/BNe3kYwy8rFXCgDh9g3uyKwoK0vQavHn0g P0yjj7mXc2Xqxx+pheXoDAGIi0SQQ8D5vSN1m3p0WmZKjac5V5l15Vkz35lx0GwVZo1Z kTOYb5ex8nDWTC9C9AMeasVjS1g4kx+uvY44FlwHcHyzKGUHrVoKcD3JzqeSB7bGfgRc Hztg== 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=mynFxL12SQF4lSRhsJTtRSX2OewF4sD0aLaXOzgVxS4=; b=YSZ8hQjINi/Sdq/29zAhCycuk9U8ZLaqgzlyb/S0SopXUPuyK4H9BslwNoVP+XR8J+ pIRQikTTx1G29R93qPN07eoMhRLEZKvQGI0+6Te1Iuu5FmOoO7CQ+iieXNsluhxQpT4/ y0heWDlJ9mhb6xWe3iTYAjevRHC+9ioMAizVaGBGAMloLqFVYX5PjcVCTj3ofV2RDZL7 Q4lVk2iSHq+l2GqWoHXIxCGTH2C6YwDrjLQgHHD94U4SRXW9uo/GHA6AGPaQ3lWbMpx7 dc+ksChq2A0x9pD/bxO49XOpicHh3R3Etp4aRSmy3NErI5ZZMxwQ84KhcqSHJ+VKF8LD 0nfA== X-Gm-Message-State: APt69E2rnAOfsfEMFvKSdM7Gzg0j0CC1bLvpzTt2eAjoyuiYZLEbRc2F GLD7+zT2oAnKNG7M+kWkp6CO6Q== X-Google-Smtp-Source: ADUXVKKK+Y+tngTdytYcaPf3p0tkgCxTL2Oxs+pvb3kMxq1J1nfX5iND/OY7QEZ/rQZW40i2tMis+A== X-Received: by 2002:a0d:e88f:: with SMTP id r137-v6mr502364ywe.160.1527991176293; Sat, 02 Jun 2018 18:59:36 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 2002:a25:b90e:: with SMTP id x14-v6ls9351090ybj.14.gmail; Sat, 02 Jun 2018 18:59:35 -0700 (PDT) X-Received: by 2002:a25:d68d:: with SMTP id n135-v6mr687301ybg.6.1527991175217; Sat, 02 Jun 2018 18:59:35 -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:38455 Archived-At: ------=_Part_19391_1506462426.1527991174651 Content-Type: multipart/alternative; boundary="----=_Part_19392_61113823.1527991174651" ------=_Part_19392_61113823.1527991174651 Content-Type: text/plain; charset="UTF-8" On Saturday, June 2, 2018 at 7:57:30 PM UTC-4, Omer Rosler wrote: > > The problem with second approach the user now has to remember two versions > of the same concepts: one to use and one to implement. > How many times have you used an iterator? I bet it's several orders of magnitude more often than you've *written one*. Yes, your library has two concepts. But they aren't two versions of the *same* concept. There's the Iterator concept, and there's the ThingThatThisToolTurnsIntoAnIterator concept. Those aren't the same thing; indeed, more likely than not, they are quite dissimilar. They have different interfaces and different purposes. Users don't have to remember the ThingThatThisToolTurnsIntoAnIterator concept, because they simply don't use it very often. When they need to use it, they'll look up what it does and how it works. What they're going to *remember* is Iterator, because that's what they're using most of the time. -- 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/48f336e3-146b-4317-8a60-1a3acc16af4b%40isocpp.org. ------=_Part_19392_61113823.1527991174651 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Saturday, June 2, 2018 at 7:57:30 PM UTC-4, Omer Rosler= wrote:
<= div>
The problem with second approach the user now has to remember two = versions of the same concepts: one to use and one to implement.
=

How many times have you used a= n iterator? I bet it's several orders of magnitude more often than you&= #39;ve written one.

Yes, your library has t= wo concepts. But they aren't two versions of the same concept. T= here's the Iterator concept, and there's the ThingThatThisToolTurns= IntoAnIterator concept. Those aren't the same thing; indeed, more likel= y than not, they are quite dissimilar. They have different interfaces and d= ifferent purposes.

Users don't have to remembe= r the ThingThatThisToolTurnsIntoAnIterator concept, because they simply don= 't use it very often. When they need to use it, they'll look up wha= t it does and how it works. What they're going to remember is It= erator, because that's what they're using most of the time.

--
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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/48f336e3-146b-4317-8a60-1a3acc16af4b= %40isocpp.org.
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