fn matmul(comptime T: type, a: [][]T, b: [][]T, c: [][]T) void {}

fn translate(x: f64, y: f64) [3][3]f64 {
    return [_][_]f64{
        [_]f64{ 1, 0, x },
        [_]f64{ 0, 1, y },
        [_]f64{ 0, 0, 1 },
    };
}

test "translate" {
    const point = [2][1]f64{
        [_]f64{2},
        [_]f64{1},
    };

    const actual = [_][1]f64{[_]f64{0}} ** 2;
    const translation = translate(-3, 1);
    try matmul(f64, translation[0..], point, &actual);

    const expected = [_][_]f64{
        [_]f64{-1},
        [_]f64{2},
    };

    assert(std.mem.equal(f64, actual, expected));
}