Given 3 java classes, Container extends Box and Box extends Dimension and I am trying to port them in Elixir
and it is extremly counterintuitive.

# https://github.com/skjolber/3d-bin-container-packing/blob/master/src/main/java/com/github/skjolberg/packing/Box.java
public class Dimension {
  protected int width; // x
  protected int depth; // y
  protected int height; // z
  protected long volume;
  protected final String name;

  public Dimension() {
    this(null);
  }

  public Dimension(String name, int w, int d, int h) {
    this.name = name;

    this.depth = d;
    this.width = w;
    this.height = h;

    calculateVolume();
  }

  protected void calculateVolume() {
    this.volume = ((long)depth) * ((long)width) * ((long)height);
  }
}

# https://github.com/skjolber/3d-bin-container-packing/blob/master/src/main/java/com/github/skjolberg/packing/Dimension.java
public class Box extends Dimension {
  final int weight;

  public Box(int w, int d, int h, int weight) {
    super(w, d, h);

    this.weight = weight;
  }
}

# https://github.com/skjolber/3d-bin-container-packing/blob/master/src/main/java/com/github/skjolberg/packing/Container.java
public class Container extends Box {
  private int stackWeight = 0;
  private int stackHeight = 0;
  private ArrayList<Level> levels = new ArrayList<>();

  public Container(Container container) {
    super(container.getName(), container.getWidth(), container.getDepth(), container.getHeight(), container.getWeight());
  }
}

And I am heading to this direction

defmodule Foo.Dimension do
  alias Foo.{Box, Dimension}
  defstruct [:name, :width, :depth, :height, :volume]

  defmacro __using__(_opts) do
    quote do
      @spec calculate_volume(%Dimension{}) :: %Dimension{}
      def calculate_volume(%Dimension{} = dimension) do
        volume = dimension.depth * dimension.width * dimension.height
        %{dimension | volume: volume}
      end
      ....
    end
  end
end

defmodule Foo.Box do
  use Foo.Dimension
  alias Foo.{Box, Dimension}
  @enforce_keys [:weight]
  defstruct [:name, :weight, :width, :depth, :height, :volume]
end

defmodule Foo.Container do
  use Foo.Dimension
  alias Foo.{Container, Dimension}
  defstruct [:volume, stack_weight: 0, stack_height: 0, width: 0, depth: 0, height: 0, weight: 0...]
end

The problems I am having are:

1. I have to repeat the base struct [:name, :width, :depth, :height, :volume] from Dimension all the way up to the top extender(Container)
2. What is the best way to deal with the Dimension constructor that calls calculateVolume()? If extender(Box or Container) do a super() call, how does it initiate :volume? Do I have to

  %Container{...} |> Container.calculate_volume()
  %Box{...} |> Box.calculate_volume()

3. I am not sure if it is a good idea to mimic the inheritance like that in Foo.Dimension by using defmacro __using__(_) do