220 3597 <2055e281-08bf-4b00-aeef-22494c9a6c08@isocpp.org> article Path: news.gmane.org!not-for-mail From: temptony@freemail.hu Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: "break break ;" etc. to break out of nested loops Date: Fri, 5 Apr 2013 13:16:41 -0700 (PDT) Lines: 126 Approved: news@gmane.org Message-ID: <2055e281-08bf-4b00-aeef-22494c9a6c08@isocpp.org> References: <1f964e4b-2762-43b8-85e5-41392926b07a@isocpp.org> <85c0ae97-3440-4a81-96c2-1af7ebb892ba@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_2294_8534313.1365193001161" X-Trace: ger.gmane.org 1365274100 8141 80.91.229.3 (6 Apr 2013 18:48:20 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 6 Apr 2013 18:48:20 +0000 (UTC) Cc: temptony@freemail.hu To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCF55ZN354IBBKXC7SFAKGQELYY7RLY@isocpp.org Sat Apr 06 20:48:20 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oa0-f69.google.com ([209.85.219.69]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1UOXGV-0007ti-0F for gclcip-std-proposals@m.gmane.org; Sat, 06 Apr 2013 19:50:59 +0200 Original-Received: by mail-oa0-f69.google.com with SMTP id k14sf28118122oag.8 for ; Sat, 06 Apr 2013 10:50:58 -0700 (PDT) X-Received: by 10.182.113.69 with SMTP id iw5mr3342427obb.33.1365193002732; Fri, 05 Apr 2013 13:16:42 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.182.132.193 with SMTP id ow1ls494077obb.58.gmail; Fri, 05 Apr 2013 13:16:41 -0700 (PDT) X-Received: by 10.182.153.194 with SMTP id vi2mr306227obb.37.1365193001917; Fri, 05 Apr 2013 13:16:41 -0700 (PDT) In-Reply-To: <85c0ae97-3440-4a81-96c2-1af7ebb892ba@isocpp.org> X-Original-Sender: temptony@freemail.hu Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: 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:3597 Archived-At: ------=_Part_2294_8534313.1365193001161 Content-Type: text/plain; charset=ISO-8859-1 It's not the business of the C++ standard to push programmers towards keeping their functions simple! Nothing you say speaks against allowing *break break...* into the language. On Friday, April 5, 2013 9:53:33 PM UTC+2, Andrew Sandoval wrote: > > On Friday, April 5, 2013 2:23:33 PM UTC-5, temp...@freemail.hu wrote: >> >> I hesitate to suggest this simple enhancement to the language, because >> it's so obvious that *somebody* must have thought of it before. In which >> case there must have been a good reason for rejecting it! But here goes: >> >> *Problem* >> The *break* statement jumps out of the nearest enclosing *do, for, >> switch, *or *while *statement. All programmers know that breaking out of >> a nested for-loop to the *second*-nearest enclosing *do, for, switch, * >> or *while *statement is a pain, and requires a *goto* statement or worse. >> >> *Suggestion* >> I suggest the following syntax: >> >> The *break break* statement jumps out of the second-nearest enclosing *do, >> for, switch, *or *while *statement. >> The *break break* *break *statement jumps out of the third-nearest >> enclosing *do, for, switch, *or *while *statement. >> The *break break* *break break *statement jumps out of the >> fourth-nearest enclosing *do, for, switch, *or *while *statement. >> >> And so on. For instance: >> >> for (int i = 0 ; i < 10 ; i++) >> for (int j = 0 ; j < 10 ; j++) >> for (int k = 0 ; k < 10 ; k++) { >> // do stuff >> if (a[i][j][k] == 0) break break break ; // the same as "goto >> ContinueExecution ;" >> } >> ContinueExecution: >> >> Easy to understand. Easy to implement. 100% backwards compatible. What's >> not to like? >> > > How about *return*? That way you are pushed towards keeping your > functions simple. > Not trying to be negative, but that seems like something you wouldn't hit > too often in C++ code -- C, yes, but hopefully not C++. > > -Andrew Sandoval > > -- --- 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/?hl=en. ------=_Part_2294_8534313.1365193001161 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable It's not the business of the C++ standard to push programmers towards keepi= ng their functions simple! Nothing you say speaks against allowing break= break... into the language.

On Friday, April 5, 2013 9:53:= 33 PM UTC+2, Andrew Sandoval wrote:
On Friday, April 5, 2013 2:23:33 PM UTC-5, temp...@freemail.hu= wrote:
I hesitate to suggest this s= imple enhancement to the language, because it's so obvious that somebody= must have thought of it before. In which case there must have been a g= ood reason for rejecting it! But here goes:

Prob= lem
The break statement jumps out of the nearest = enclosing do, for, switch, or while statement. All programmer= s know that breaking out of a nested for-loop to the second-nearest = enclosing do, for, switch, or while state= ment is a pain, and requires a goto statement or worse.

Suggestion
I suggest the following synta= x:

The break break statement jump= s out of the second-nearest enclosing do, for, switch, or&= nbsp;while statement.
The break brea= k break statement jumps out of the third-nearest = enclosing do, for, switch, or while state= ment.
The break break break break&nb= sp;statement jumps out of the fourth-nearest enclosing do, for,= switch, or while statement.

And so on. For instance:

for (int i =3D 0= ; i < 10 ; i++)
  for (int j =3D 0 ; j < 10 ; j++)
    for (int k =3D 0 ; k < 10 ; k++) {
&= nbsp;     // do stuff
      if (a[i][j][= k] =3D=3D 0) break break break ; // the same as "goto ContinueExecution ;"<= /div>
    }
ContinueExecution:

Easy to understand. Easy to implement. 100% backwards compatible. = What's not to like?

How about http://groups.google.com/a/isocpp.org/group/std-pro= posals/?hl=3Den.
 
 
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