Vec example

import std.stdio;

struct Vec(size_t dim) {
  float[dim] data;

  //forward all unsupported operations to data
  alias data this;

  //operate over variadic arguments as if they were an array
  //at the same time, restrict the amount of arguments to dim
  this(float[dim] floats...) {
    data[] = floats;
  }

  auto crossProduct(ref Vec!dim other) {
    static if (dim == 2) {
      return data[0]*other[1] - data[1]*other[0];
    }
    else static if (dim == 3) {
      return Vec!dim(data[1]*other[2] - data[2]*other[1],
                     data[2]*other[0] - data[0]*other[2],
                     data[0]*other[1] - data[1]*other[0]);
    }
    else static assert (0, "Not implemented");
  }
}

void main() {
  Vec!2 xy1 = Vec!2(1, 2),     xy2 = Vec!2(3, 4);
  Vec!3 xyz1 = Vec!3(5, 6, 7), xyz2 = Vec!3(8, 9, 10);

  float res1 = xy1.crossProduct(xy2);
  Vec!3 res2 = xyz1.crossProduct(xyz2);

  writeln(res1, " | ", res2);
}