Re: Error on recursive alias

[bearophile]

Johan Mollevik:

x and y are the two dimensional indices into the 4x4 array block and v

is the vallue at block[y][x]

OK. Something like this?


import std.stdio, std.typecons;

struct NaturalScan(T) {
    T[][] data;
    size_t r, c;

    @property bool empty() const pure nothrow {
        return r == data.length;
    }

    @property Tuple!(size_t, size_t, T) front()
    const pure nothrow {
        return typeof(return)(r, c, data[r][c]);
    }

    void popFront() pure nothrow {
        c = (c + 1) % data[r].length;
        if (c == 0)
            r++;
    }
}

NaturalScan!T naturalScan(T)(T[][] m) {
    return typeof(return)(m);
}

void main() {
    auto mat = [[10, 20], [30, 40, 50], [60, 70]];
    foreach (r, c, v; mat.naturalScan)
        writefln("%d %d %d", r, c, v);
}


Bye,
bearophile