🚀 go-pugleaf

andrewd@agnus.livewire.com.au (Andrew Dunbar) wrote:
>Greg Comeau (comeau@panix.com) wrote:
[snip]
>: The real problem I have with this proposal is that it only considers `for'
>: (and probably `while').  If to be stronger, it could be more general than
>: just those, plus consider appropriateness of special cases.
>: Even with that though, no doubt we still wouldn't see it fly...
>: 
>I intended them to be used in any construct where a break would apply:
>do, for, switch, while
>
>Somebody mentioned 'if' but I couldn't see a use for it.

Oh, I'm sure somebody'd find a use for it and really like it. Here's
how it could be (ab)used with an if statement.

    void manipulate_the_windows(Window *top)
    {
        Window *A = NULL, *B = NULL *C = NULL;

        if check_parms (top == NULL)
            break check_parms;
        else {
            do_something_with_window(top);
            A = get_subwindow(top);
            if (A == NULL)
                break check_parms;

            do_something_different_with_window(A);
            B = get_subwindow(A);
            if (B == NULL)
                break check_parms;

            do_something_with_window(B);
            C = get_subwindow(B);
            if (C == NULL)
                break check_parms;

            /* All windows I'm looking for are good, so do it  */
            do_something_weird_with_four_windows(top,A,B,C);

            return;
        }

        /* Do error handling here */
    }

Ugly, huh, early return and all? People do this sort of thing, though.
What the programmer is doing here would be better served by a labeled
compound statement and breaks to leave it (or situation indicators).
Gotos are currently used. IMO, though, the best solution would be to
rewrite the logic as something more conventional.

BTW, this example came from something someone posted to comp.std.c
awhile back. Look familiar?

-- 
Paul Long         plong@perf.com       http://www.teleport.com/~pciwww/
  "A perfect method should not only be an efficient one, as respects
  the accomplishment of the objects for which it is designed, but
  should in all its parts and processes manifest a certain unity and
  harmony." - George Boole, _An Investigation of the Laws of Thought_