220 25034 <6c282596-68ad-4e61-a137-6142ae5d9c16@isocpp.org> article Path: news.gmane.org!not-for-mail From: "'Walt Karas' via ISO C++ Standard - Future Proposals" Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: "Components" template with implicitly defined partial specializations for all classes Date: Mon, 7 Mar 2016 11:33:30 -0800 (PST) Lines: 111 Approved: news@gmane.org Message-ID: <6c282596-68ad-4e61-a137-6142ae5d9c16@isocpp.org> 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> <39bbeb02-62b8-497b-8d65-5780a6baca97@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_447_1339118543.1457379210230" X-Trace: ger.gmane.org 1457379233 14696 80.91.229.3 (7 Mar 2016 19:33:53 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 7 Mar 2016 19:33:53 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDFLZXWOVYIBBC5P663AKGQETDKMHBY@isocpp.org Mon Mar 07 20:33:35 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oi0-f69.google.com ([209.85.218.69]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ad0uK-0003il-MF for gclcip-std-proposals@m.gmane.org; Mon, 07 Mar 2016 20:33:32 +0100 Original-Received: by mail-oi0-f69.google.com with SMTP id m82sf152644482oif.1 for ; Mon, 07 Mar 2016 11:33:32 -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=QlYQoHAM0iV2HB2MhAu/BNn/tEnCy/y+PTGNrDL3QU4=; b=XUpdGv7gs44mkL+CiNVLvEjJNj97vs+rkuWkTpleAfA0+N9vzKU1Z49bnuZc9DPXVA l2LEaYgavapioV9AaeuJWS8w3DuTnu5wo16KK/KmOYDh1ZArItX5bJJP/XwOFgOoTHS6 +miYaV2l1pUlCAmn/zWeUTpS2NYEWlUVEXRwX9EkyfXOKFSj0HRL574p9YTht2xhF8WY Ecj5G7y6WHSSSlqRdTd3UqyuFXMfR3ObcK4oTK/D9PJYETbTonZLrfeam5zwdK/9BBPb W24FTLiAcAwcU788J0baUhfh+M4Iz9EFlv3fx6u+f/CbNdIuQE6PFakPXSsfUhuSsgja BQVw== 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=QlYQoHAM0iV2HB2MhAu/BNn/tEnCy/y+PTGNrDL3QU4=; b=RNmBxGK5Mnh1TrOV5UVMHhjH6SHs4XMH9FnLWaQoNpmOry0aYK3esKggooF0zgDdx1 GPQgjs9C4iXBPmJjeZSIkIZgcVxZybJAFRLHOTIJoQqinWivHXurRWqTvlFhUf9CrXvv wWGlXEXd5Lyjvf3BKieuiWwwgNmBGmV0+9Ha2s/p2jMjG341t50NgvXQKopAD2uMkU0p vpWB46XVK0VN0VIajljMr5zfFQb2ew/MaZGdtmmTKlsL429aLR7v4k8vH3OKwuyf4L4T si21xkrw08J4HPwW+pMtHcQ8C4ticgUqhN3PT8pn+z3CWGsUpztEdNSFVT5OGFamt60G RKjg== X-Gm-Message-State: AD7BkJKRvYX5PqmX5mhSM9/1pl7pZM/CA5qkp/Cg2ankKqFQ9U6ka/kJavuhxArLugBpYQ== X-Received: by 10.182.233.170 with SMTP id tx10mr18431693obc.18.1457379211826; Mon, 07 Mar 2016 11:33:31 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.29.82 with SMTP id d79ls1039703iod.24.gmail; Mon, 07 Mar 2016 11:33:30 -0800 (PST) X-Received: by 10.50.138.165 with SMTP id qr5mr246135igb.10.1457379210856; Mon, 07 Mar 2016 11:33:30 -0800 (PST) In-Reply-To: <39bbeb02-62b8-497b-8d65-5780a6baca97@isocpp.org> X-Original-Sender: wkaras@yahoo.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: , X-Original-From: Walt Karas Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:25034 Archived-At: ------=_Part_447_1339118543.1457379210230 Content-Type: multipart/alternative; boundary="----=_Part_448_2122990370.1457379210230" ------=_Part_448_2122990370.1457379210230 Content-Type: text/plain; charset=UTF-8 On Sunday, March 6, 2016 at 2:40:30 PM UTC-5, Cleiton Santoia wrote: > > >> Experience has shown that good layered architectures are generally >> advantageous. A rule of thumb for a good layered architecture is to have >> one capability in a lower layer that supports multiple capabilities in a >> higher layer. As opposed to supporting just one or some or all of those >> multiple capabilities in the lower layer. The base language is the lowest >> layer of the C++ architecture. Therefore, I think it's likely to be better >> to have a capability in the base language that allows for support of >> reasonably good generic comparison operators, generic stream input/output >> operators, generic std::hash, maybe generic JSON/XML input/output, etc >> using library code above the base layer. >> > > In the both reflection proposals there are a sample of JSON serialization > (in sligtly different ways), but both static and without "mapping" > functions. > You dont need that "Component" structure you proposed, you just expand the > pack thru folding. > > Here the code your > 10 liner 'operator ==' lib-olny on top of reflection ( from line 8 to 18 ). > > Please pay attention on lines 10 and 16, in 10 we have a "template > folding" and in 16 we have the only line that will change after reflection > be accepted (hopefully). > In line 10 it might be good to replace c1.*m == c2.*m with a function within a class template with simple == as its base definition. The motive being that this class template could be specialized to "fix" the default == rather than discarding it if simple == wasn't appropriate for a few components among many. -- 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/6c282596-68ad-4e61-a137-6142ae5d9c16%40isocpp.org. ------=_Part_448_2122990370.1457379210230 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Sunday, March 6, 2016 at 2:40:30 PM UTC-5, Clei= ton Santoia wrote:

Experience has shown that good layered architectures are generally a= dvantageous. =C2=A0A rule of thumb for a good layered architecture is to ha= ve one capability in a lower layer that supports multiple capabilities in a= higher layer. =C2=A0As opposed to supporting just one or some or all of th= ose multiple capabilities in the lower layer. =C2=A0The base language is th= e lowest layer of the C++ architecture. =C2=A0Therefore, I think it's l= ikely to be better to have a capability in the base language that allows fo= r support of reasonably good generic comparison operators, generic stream i= nput/output operators, generic std::hash, maybe generic JSON/XML input/outp= ut, etc using library code above the base layer.

In the both reflection proposals there are a sample of JS= ON serialization (in sligtly different ways), but both static and without &= quot;mapping" functions.
You dont need that "Compon= ent" structure you proposed, you just expand the pack thru folding.=C2= =A0

Here the code=C2=A0your 10 = liner 'operator =3D=3D' lib-olny on top of reflection ( from line 8= to 18 ).=C2=A0

Please pay attention on lines = 10 and 16, in 10 we have a "template folding" and in 16 we have t= he only line that will change after reflection be accepted=C2=A0(hopefully)= ..

In line 10 it might be good to replace c= 1.*m =3D=3D c2.*m with a function within a class template with simple =3D= =3D as its base definition.=C2=A0 The motive being that this class template= could be specialized to "fix" the default =3D=3D rather than dis= carding it if simple =3D=3D wasn't appropriate for a few components amo= ng many.

--
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To view this discussion on the web visit https://groups.google.= com/a/isocpp.org/d/msgid/std-proposals/6c282596-68ad-4e61-a137-6142ae5d9c16= %40isocpp.org.
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