Re: Suggested extention of the break statement

From:

"karthikeyan.radhakrishnan@gmail.com" <karthikeyan.radhakrishnan@gmail.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Mon, 10 Sep 2007 16:30:15 CST

Message-ID:

<1189446894.294277.225370@k79g2000hse.googlegroups.com>

On Aug 23, 4:11 pm, Hyman Rosen <hyro...@mail.com> wrote:

Gerard J. Cerchio wrote:

I would like have a break statement within a try statement transfer control
out of the try. The try is already a transfer control statement and there is
no current sematic for a break within the try.

The current single-level break and continue statements are
inadequate for many reasonable loop structures anyway. C++
should take a page from Ada and allow 'break label;' and
'continue label;' where label is attached to a statement.
(We would require that the label for a continue actually
label a loop, but any statement could have a break label.)
So,

     t1: try {
         stuff();
         if (condition()) {
             break t1;
         }
     } catch (...) {
         handle();
     }

     f1: for (int i = 0; i < 100; ++i) {
             for (int j = 0; j < i; ++j) {
                 if (no_good(j)) {
                     continue f1;
                 }
             }
             cout << i << " is good!" << endl;
         }

     w1: while (cin >> ch) {
             switch(ch) {
             case 'Q': break w1;
             case '+': do_add(); break;
             default: sing(); break;
             }
         }

     i1: if (c1) {
             x();
             if (c2) {
                 break i1; //----
             } // |
             y(); // |
         } else if (c3) { // |
             z(); // |
         } else { // |
             w(); // |
         } // |
         // goes here <----------

Well, wouldn't that be like going back in time ? I guess this takes
you back to issues with GOTO.

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