Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!pacbell!att-ih!att-cb!clyde!watmath!rbutterworth
From: rbutterworth@watmath.waterloo.edu (Ray Butterworth)
Newsgroups: comp.lang.c
Subject: Re: Another "D" idea (Oh no, not again!)
Message-ID: <17900@watmath.waterloo.edu>
Date: 29 Mar 88 14:54:00 GMT
References: <1170@ucsfcca.ucsf.edu> <316@wsccs.UUCP> <2571@cognos.UUCP>
Organization: U of Waterloo, Ontario
Lines: 40

In article <2571@cognos.UUCP>, brianc@cognos.uucp (Brian Campbell) writes:
> In article <316@wsccs.UUCP> val@wsccs.UUCP (Val Kartchner) writes:
> > I also think that there should be something like "break 'n';" (Where
> > 'n' is a constant integer.  Variables would be interesting and floats
> > highly ambiguous.)  I've often been deep in multiple loops, and wanted
> > to get out a few levels.
> My suggestion was to add labels to looping constructs:
>     while (...) :top
>         while (...)
>             break :top;
>         if (...)
>             continue :top;
> The label is far less confusing and requires less maintenance than
> specifying the number of levels to exit.  It should also make the
> compiler's job easier since it is specifically told that interior
> statement blocks may be exited abnormally.

But that is not really any clearer than what is already available
in the language:


    for ( ; 0 != (file=fopen(...)); fclose(file)) samefile: {

        while (0 != (line = fgetl(...))) sameline: {

            for (index=0; 0 != (c=line[index]); ++index) samechar: {

                ...
                if (blah()) goto nextfile;
                blahblah();
                if (blahblahblah()) goto sameline;
                ...

                nextchar:;
            }
            nextline:;
        }
        nextfile:;
    }

And I don't feel the slightest guilt in using "goto" in this way.