Row Polymorphism example in Elixir

row_poly.ex

defmodule Point2D do
  defstruct [x: 0, y: 0]
end

defmodule Point3D do
  defstruct [x: 0, y: 0, z: 0]
end

defmodule RowPolymorphism do
  def get_x_y(%{x: x, y: y} = _data) do
    {x, y}
  end
end

p1 = %Point2D{x: 10, y: 3}
p2 = %Point3D{x: 1, y: 5, z: 11}

RowPolymorphism.get_x_y(p1)
#=> {10, 3}

RowPolymorphism.get_x_y(p2)
#=> {1, 5}