Re: Indexed foreach on struct?

[H. S. Teoh]

On Mon, Jan 23, 2012 at 03:32:07PM -0500, Matt Soucy wrote:
> So I was messing around with some code I've been writing recently,
> and I wanted to use a foreach on a struct as if it were an
> associative array. The problem is, I can't find any information on
> how to do that.
[...]
> I don't see any sort of opApply or similar to do this, and the
> foreach section of dlang.org doesn't help. Is there a way to do it,
> or do I need to do a workaround?
[...]

You can use opApply. Sample test program:

        struct Test {
                int opApply(int delegate(ref int) dg) {
                        auto ret = 0;
                        for (auto i=0; ret==0 && i<5; i++) {
                                ret = dg(i);
                        }
                        return ret;
                }
        }

        import std.stdio;
        void main() {
                Test t;

                foreach (n; t) {
                        writeln(n);
                }
        }

Program prints:

        0
        1
        2
        3
        4

Hope that helps.


T

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