import std;

​

struct Point4 {

    Tuple!(

        float, "x",

        float, "y",

        float, "z",

        float, "w"

    ) coords;

    alias coords this;

    this(float x, float y, float z, float w)

    {

        coords = tuple(x, y, z, w);

    }

}

​

// check for no UB

static assert( Point4.sizeof == 16 );

​

void main() {

    Point4 p = Point4(1, 2, 3, 4);

    p[2].writeln;

    assert( p[2] == p.z );

    p[0] = 5;

    assert(p.x == 5);

    //p[5] = 0; // Error: array index [5] is outside array bounds [0 .. 4]

​

}