From 1632839177538614391 X-Google-Thread: 7894ca11fe,d47b345505a72a70 X-Google-Attributes: gid7894ca11fe,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!news1.google.com!newsfeed.stanford.edu!news.kjsl.com!news.alt.net!frodo.cs.rpi.edu!not-for-mail From: Jared Grubb Newsgroups: comp.std.c++ Subject: Re: for-else: adding else to for loops Date: Tue, 11 Aug 2009 14:06:10 CST Organization: http://groups.google.com Lines: 39 Sender: cppmods@cs.rpi.edu Approved: austern@google.com Message-ID: <84af1815-994d-48d6-9c07-c8965bba0d01@b25g2000prb.googlegroups.com> References: <5d82cd6c-2a22-4dd7-8c7d-790b579533ea@d15g2000prc.googlegroups.com> NNTP-Posting-Host: netlab.cs.rpi.edu Content-Type: text/plain; charset=ISO-8859-1 To: (Usenet) Return-Path: X-Original-Date: Mon, 10 Aug 2009 10:54:02 -0700 (PDT) X-Submission-Address: std-c++@netlab.cs.rpi.edu Xref: g2news2.google.com comp.std.c++:1256 On Aug 7, 5:20 pm, brang...@cix.co.uk (Dave Harris) wrote: > jared.gr...@gmail.com (Jared Grubb) wrote (abridged): > > > In Python, loops can have an else clause; the else clause gets > >executed when the loop condition fails (but not when the loop > >is exited via a break, return, or exception). > > As it happens, a similar suggestion was made in this group on the 30th > June, by Doug Van Natter. It was pointed out then that the proposed > syntax would break existing code that preceded the for-loop with an > if-statement. Thanks for the pointer. I figured someone would have asked before, but it's one of those things that are hard to construct a search for ("for" and "else" being such common words). > In any case, I don't think there is much support for extending the > control constructs, as we've managed to get on so well for so long > without them. You point out yourself three ways to write the code. A > goto-statement will sometimes work too. So the benefit is marginal, and > strictly a "programming in the small" affair. Ah, that's a good point and not easily solvable. It is a rare control flow, but the alternatives are much harder to read -- and it's not a hard flow to squeeze into the assembly (but neither is multiple-level break, as someone else pointed out). I just thought I'd ask. Once you've seen the flow, it's hard to get out of your head when a use for it pops up! Jared -- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@netlab.cs.rpi.edu] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.comeaucomputing.com/csc/faq.html ]