220 25013 article Path: news.gmane.org!not-for-mail From: Cleiton Santoia Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: "Components" template with implicitly defined partial specializations for all classes Date: Sun, 6 Mar 2016 19:45:23 -0800 (PST) Lines: 118 Approved: news@gmane.org Message-ID: References: <56D9E17F.2070202@wanadoo.fr> <2b0bcca0-0939-49f7-939b-4d688f8dfe34@isocpp.org> <324dbff9-84da-46f2-b2f3-3d9fe0cc2082@isocpp.org> <56DA88DF.90000@wanadoo.fr> <7e46c46d-2e18-4cec-92c1-4f4d7fbc786b@isocpp.org> <56DC58FC.9020009@wanadoo.fr> <8922074a-fe00-4476-a8ef-8ba5840e1338@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_680_1974804935.1457322323372" X-Trace: ger.gmane.org 1457322332 12113 80.91.229.3 (7 Mar 2016 03:45:32 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 7 Mar 2016 03:45:32 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCBMVWMTUUNBBVHS6O3AKGQEHTUS5RI@isocpp.org Mon Mar 07 04:45:27 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ob0-f198.google.com ([209.85.214.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1acm6o-00081R-0r for gclcip-std-proposals@m.gmane.org; Mon, 07 Mar 2016 04:45:26 +0100 Original-Received: by mail-ob0-f198.google.com with SMTP id rt7sf135772027obb.0 for ; Sun, 06 Mar 2016 19:45:25 -0800 (PST) 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=S1k22pMYY/cAcCbxWnLuUWkwPoVPEGKvxgRaEdKmunU=; b=K+97PhJAgLsi0OO0euF5rYLBafX3NTNXwHBejcJN3UNcOubnUWqgB/IuW9Jq1kx8ru NUxDk8XLKbdS2R38OXOtC+KiMLD0wwhVyR1p/k0GIeRPcq8WRTTpOtru2z3FzYoq7pfL GEBcKpnARUCA0CXMiBiRhuy6qFJub6ux0UYhqM78dsPaZ2XGDAh2JbveoOqTTRCUUKcu HOPfGlYy2k2n+tXz4cllAOgvJ7PLCfH6GgbhhH4iZYxb8R75iofYVn2cHKkkdP8lu4zs SM8hmstPbVb+z+Gkui0nIt1h/y9Rv3twY3kSkupDGzLD4xV59zkShaVtOr/pgw+UMNUb qWqg== 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 :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=S1k22pMYY/cAcCbxWnLuUWkwPoVPEGKvxgRaEdKmunU=; b=ViyqLXV/EHhJGopHw3XSvfl1RzlpsQaSaSzZ+hi1dzoPUQrHqvi2XZqIv2UCyozMmt JCaizCoo1yLijizDNAGgO/SVNnkyTJFSIM0UY0BTJ9XFgjG33+/eTa3tHUM3R/r4hEbY uTXD4FABwbyfouhxA5LiLNMA7GIxV5iXNeQiypK5Tso9wTUBIblVSmutXNsfaqVFsN14 lLoR6D+f/9Wl1YT9kHu4TeOBmFVjmps+F3H4cY+9C5A0WF3blCAfNLNnYOrTJ6c3XTFk x/wp2txBcluIvaoxJNli6Je31l4JIlCOTJMNZTFMbQ1SAOIcoUiQCGLPM2bHlP3gTIzM 5ziA== 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: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=S1k22pMYY/cAcCbxWnLuUWkwPoVPEGKvxgRaEdKmunU=; b=ObdmCyvLnwBsgiSWy/KkIiUjpzUeLOlBINJ7mSXXBDXsp8c09vbj4qAAlYdx/8JVX+ ORek/nhaA0iwXM6CDJ7x4iQ6qxvN1Ivsn8o0d6d/ASVyPIA/NztZ3sTWA77uq5cZw9gG k0V+vEZ/csdtypWG8DgfZLvH0ZCPMUHG6S5UF5ftH1w4/gW4JF//M+0s+A09GiZm7sSD 74jcn5Mhzrmk0bAfso0V8qN5By0R5q1yNIHR2XrbUvfKgRztd6XSkOzIAxHtnk7a6eVX 7L1jrl9jmPa8ZECvNvDoNGqaH6+llsYkbQ1AJg7RPU0fZ5Q5pA7jiBvyAuBQncJYdnrw vh5A== X-Gm-Message-State: AD7BkJLPlmovuIlnLsHn8G0+X6XkMFC6Du4zgzbS+8Ns6bi2a7sKOP+N9Th1LvVsD/LBXA== X-Received: by 10.107.41.79 with SMTP id p76mr15963424iop.21.1457322325157; Sun, 06 Mar 2016 19:45:25 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.73.226 with SMTP id o2ls784352igv.8.gmail; Sun, 06 Mar 2016 19:45:24 -0800 (PST) X-Received: by 10.50.142.39 with SMTP id rt7mr161245igb.8.1457322324097; Sun, 06 Mar 2016 19:45:24 -0800 (PST) In-Reply-To: <8922074a-fe00-4476-a8ef-8ba5840e1338@isocpp.org> X-Original-Sender: cleitonsantoia@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:25013 Archived-At: ------=_Part_680_1974804935.1457322323372 Content-Type: multipart/alternative; boundary="----=_Part_681_2132948118.1457322323372" ------=_Part_681_2132948118.1457322323372 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable > > I suggested one possibility, for "Components" to be a default public clas= s=20 > member. "Components" could also be a default protected class member. So= =20 > the class would have to friend a helper class of comparison or other=20 > operator templates in order for the default operator to work for the clas= s.=20 > =20 > Something like this was suggested before, it's a form "intrusive"=20 reflection, when you (or the compiler) must change something inside the=20 class to make it reflective, the comitee pronouced that it's not what they= =20 want. How do you handle classes of a library that you don't have protected access= =20 to it ? Some library that is not yours to change the code ? or a static=20 library ? =20 > A big issue would be, should users of something as basic as comparison=20 > operators have to deal with template use error hell-spew? =20 > But even the most casual users of C++ should still be using the STL,=20 > shouldn't they? I'm not sure it's reasonable to shelter even them from= =20 > template hell-spew. > Regarding the error messages, are you aware of concepts lite=20 ? This= =20 is a work to overcome the problem of template error messages (among others)= .. A casual user must rely in the easy-to-use library solution and the library= =20 solution may use hell-spew meta-programming tricks in it=C2=B4s implementat= ion. =20 BR CSS --=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/c84fe5fd-00be-4329-9f6e-0c177c61f3de%40isocpp.or= g. ------=_Part_681_2132948118.1457322323372 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
I suggested one possibility, for "Components" to be a de= fault public class member. =C2=A0"Components" could also be a def= ault protected class member. =C2=A0So the class would have to friend a help= er class of comparison or other operator templates in order for the default= operator to work for the class. =C2=A0

Something like this was suggested before, it's a form &qu= ot;intrusive" reflection, when you (or the compiler) must change somet= hing inside the class to make it reflective, the comitee pronouced that it&= #39;s not what they want.
How do you handle classes of a li= brary that you don't have protected access to it ? Some library that is= not yours to change the code ? or a static library ?

<= div>=C2=A0
A big issue would be, should users of something as= basic as comparison operators have to deal with template use error hell-sp= ew? =C2=A0
But even the most casual users of C++ should st= ill be using the STL, shouldn't they? =C2=A0I'm not sure it's r= easonable to shelter even them from template hell-spew.

Regarding the error messages, are you awa= re of =C2=A0concepts lite ? This is a work to overcome the problem o= f template error messages (among others).
A casual user must rely= in the easy-to-use library solution and the library solution may use hell-= spew meta-programming tricks in it=C2=B4s implementation.
<= br>
=C2=A0
BR
CSS

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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.
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