220 22656 article Path: news.gmane.org!not-for-mail From: Andrew Tomazos Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Small contribution to readability (of at least my code) Date: Sun, 15 Nov 2015 11:24:06 +0100 Lines: 301 Approved: news@gmane.org Message-ID: References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=001a1143c04e4052a3052491b1d4 X-Trace: ger.gmane.org 1447583052 12294 80.91.229.3 (15 Nov 2015 10:24:12 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 15 Nov 2015 10:24:12 +0000 (UTC) To: "std-proposals@isocpp.org" Original-X-From: std-proposals+bncBD5KHQXXWYPRBR52UGZAKGQEDFB5S2A@isocpp.org Sun Nov 15 11:24:11 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-lb0-f200.google.com ([209.85.217.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZxuTi-0004bh-Qe for gclcip-std-proposals@m.gmane.org; Sun, 15 Nov 2015 11:24:10 +0100 Original-Received: by lbbko8 with SMTP id ko8sf43432546lbb.2 for ; Sun, 15 Nov 2015 02:24:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp_org.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:x-original-sender:x-original-authentication-results :reply-to:precedence:mailing-list:list-id:x-spam-checked-in-group :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=fUV+ldA89w8uScSdntFjG8R5b1HQ7yiw9womaDmZcoE=; b=uAKlPFM8NPdyJXZYPUBqsjdHst0dw+zQsL/Ile/71bKFZrdD6b5uRxCikkTb4+mL7i o+f4jDysOJZxJtT/kal5CInP042CcEANyFCEYUxX6LkCY+hTQyuYaQfj1crSVDHOAJ6v TYYd/+1g0T1jeV9HeBaGyia97/DxHvQXM+z4Mk3d0SBRKjqKoMcqBf9YD4krIbOj+BUv nE2BVxfT9ll6Epc0lju4aO2SfrLMN73YkDTGyvdXzU/w0d5ubfuqnTgnOmyb+vvO9xJW rCIIg15KX3VoIFbzNLJy5wnp98SPO7L5LnA7zJGT/qzApWKFjovYmmSWPGfxqRsREaGj vDPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:content-type:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=fUV+ldA89w8uScSdntFjG8R5b1HQ7yiw9womaDmZcoE=; b=Ze5Dg4F8EhYMPt275d03gtHsd+rJA+i8d3dKyXT6lGGS8kjBPYMbKGL4+8eX4NDjNm PziWwDb2QaUpgZesW1zKEaqfbJyG4oYaxFqntG2ZkWD1Jd4gL9mpEmh5rUDGtG8H8SXb e0TMJdUK+gGktnBKpia+1VS4hkNdchNSS4eeUV3a5FcNeyY1We0IZqPjTlB8vvWTrfPG 4y9PIbBBF/SwMu4gruX6qb/+Qyxj4yQsdibUwqEezW5mOh9VffOgTpk394U2xF5Ozyq+ brdov36rK4IqeVEKlfaAtYm3DTqfHtgrF9Olvxw9O3STekgktN3pLquaOQzwlCR0MFBj 7lEQ== X-Gm-Message-State: ALoCoQnABkPiznJyCMlHHWCGpyAjog1XPwnQa+G5mInX8eSej8lRoXcIHgyMz14g/3OWMSyluytq X-Received: by 10.25.81.21 with SMTP id f21mr4293461lfb.2.1447583050106; Sun, 15 Nov 2015 02:24:10 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.28.92.138 with SMTP id q132ls433021wmb.25.gmail; Sun, 15 Nov 2015 02:24:06 -0800 (PST) X-Received: by 10.28.46.137 with SMTP id u131mr12561701wmu.61.1447583046804; Sun, 15 Nov 2015 02:24:06 -0800 (PST) Original-Received: from mail-wm0-x22d.google.com (mail-wm0-x22d.google.com. [2a00:1450:400c:c09::22d]) by mx.google.com with ESMTPS id vl1si38815210wjc.33.2015.11.15.02.24.06 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 15 Nov 2015 02:24:06 -0800 (PST) Received-SPF: pass (google.com: domain of andrewtomazos@gmail.com designates 2a00:1450:400c:c09::22d as permitted sender) client-ip=2a00:1450:400c:c09::22d; Original-Received: by wmec201 with SMTP id c201so137205040wme.0 for ; Sun, 15 Nov 2015 02:24:06 -0800 (PST) X-Received: by 10.28.55.200 with SMTP id e191mr12608430wma.83.1447583046192; Sun, 15 Nov 2015 02:24:06 -0800 (PST) Original-Received: by 10.28.113.91 with HTTP; Sun, 15 Nov 2015 02:24:06 -0800 (PST) In-Reply-To: X-Original-Sender: andrewtomazos@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of andrewtomazos@gmail.com designates 2a00:1450:400c:c09::22d as permitted sender) smtp.mailfrom=andrewtomazos@gmail.com; dkim=pass header.i=@gmail.com; dmarc=pass (p=NONE dis=NONE) header.from=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:22656 Archived-At: --001a1143c04e4052a3052491b1d4 Content-Type: text/plain; charset=UTF-8 I think there is a good idea in here. Rather than making this narrow change, I'd prefer to see a larger proposal for allowing a separate forward declaration of the public interface of a class from the definition of the class. Perhaps something like: public class MyClass { MyClass(int = 0); int val() const; void val(int); }; class MyClass { public: MyClass(int = 0) { ... } int val() const { ... } void val(int) { ... } private: int val_; }; The compiler would check that the public interface forward declaration matches the later class definition. Consequently a human reader of the header file only needs to read the public interface declaration, and isn't distracted by implementation details, like inline function bodies and the private section. The interface documentation comments could be placed on this forward declared public interface. This is motivated by separating out interface specification from implementation specification, which are fundamentally separate design activities in software engineering. On Sat, Nov 14, 2015 at 10:57 PM, John Yates wrote: > Hi Larry, > > Thanks for the reply. I posted to this list because my proposal is not a > request for help but rather a suggestion for a (small) language change. It > adds no functionality so my note attempted to show how it might improve the > presentation of source. Apparently I failed to convey that clearly enough > in my previous post. > > In the following only the declaration followed by definition within a > class scope is disallowed: > > // global scope > struct S; > struct S { int i; }; > int f(); > int f() { return 0; } // OK > > // within a namespace scope > namespace N { > struct S; > struct S { int i; }; > int f(); > int f() { return 0; } // OK > } > > // within a class scope > class C { > struct S; > struct S { int i; }; > int f(); > int f() { return 0; } // ERROR! > }; > > I am proposing to allow that last case. > > /john > > > On Sat, Nov 14, 2015 at 4:42 PM, Larry Evans > wrote: > >> On 11/14/2015 01:14 PM, John Yates wrote: >> > I attempt to have one class per header. This allows me to follow a >> > file-wide organizing principle. >> > >> Hi John, >> >> I'd guess This topic is better covered in other newsgroups. >> Try googling "c++.moderated coding style" to find a better >> place to post you message. >> >> BTW, I like your idea: >> >> a name should be introduced before being described >> >> which is a rule I use. >> >> -regards, >> Larry >> >> >> >> -- >> >> --- >> 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/. >> > > -- > > --- > 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/. > -- --- 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/. --001a1143c04e4052a3052491b1d4 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
I think there is a good idea in here.

R= ather than making this narrow change, I'd prefer to see a larger propos= al for allowing a separate forward declaration of the public interface of a= class from the definition of the class.

Perhaps s= omething like:

public class=C2=A0MyClass=C2=A0{
=C2=A0=C2=A0MyClass(int =3D 0);

=C2=A0 int val() const;
=C2=A0 void val(int);
};
=
<= font face=3D"monospace, monospace">class=C2=A0MyClass=C2=A0{
public:
=C2=A0=C2=A0MyClass(int =3D 0) { ... }

=C2= =A0 int val() const { ... }
=C2=A0 void val(int) { ... }
<= div style=3D"font-size:12.8px">
private:
=C2=A0 int val_;
};

The compiler would check t= hat the public interface forward declaration matches the later class defini= tion.=C2=A0 Consequently a human reader of the header file only needs to re= ad the public interface declaration, and isn't distracted by implementa= tion details, like inline function bodies and the private section.=C2=A0 Th= e interface documentation comments could be placed on this forward declared= public interface.

This is motivated by separating out interface specif= ication from implementation specification, which are fundamentally separate= design activities in software engineering.



On Sat, Nov 14, 2015 at 10:57 PM, John Yates &l= t;john@yates-she= ets.org> wrote:
Hi Larry= ,

Thanks for the reply.=C2=A0 I posted to this list beca= use my proposal is not a request for help but rather a suggestion for a (sm= all) language change.=C2=A0 It adds no functionality so my note attempted t= o show how it might improve the presentation of source.=C2=A0 Apparently I = failed to convey that clearly enough in my previous post.

In the following only the declaration followed by definition within= a class scope is disallowed:

// global scope
struct S;
struct S { int i; };
int f() { r= eturn 0; } =C2=A0// OK

// within a name= space scope
namespace = N {
=C2=A0 struct S;
=C2=A0 struct S { int i= ; };
=C2=A0 int f();
=C2=A0 int f() { return= 0; } =C2=A0// OK
}

// within a class scope
= class C {
=C2=A0 struct S;
=C2=A0 struct S { int i; };
=C2=A0 int f();
=C2=A0 int f() { return 0; } =C2=A0// ERROR!
};

<= /div>
I am proposing to allow that last case.

/john


On Sat= , Nov 14, 2015 at 4:42 PM, Larry Evans <cppljevans@suddenlink.net<= /a>> wrote:
On 11/14/2015 01:14 PM, Joh= n Yates wrote:
> I attempt to have one class per header.=C2=A0 This allows me to follow= a
> file-wide organizing principle.
>
Hi John,

I'd guess This topic is better covered in other newsgroups.
Try googling "c++.moderated coding style" to find a better
place to post you message.

BTW, I like your idea:

=C2=A0 a name should be introduced before being described

which is a rule I use.

-regards,
Larry



--

---
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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.
Visit this group at http://groups.google.c= om/a/isocpp.org/group/std-proposals/.

--

---
You received this message because you are subscribed to the Google Groups &= quot;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.
Visit this group at http://groups.google.com/a/isocpp.org/gro= up/std-proposals/.

--

---
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
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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