protocol thingy

foo.ex

defprotocol Proto do
  def generic_getter(value)
end

defmodule A do
  defstruct [:a]
  def generic_getter(v), do: v.a
  
  defimpl Proto do
    defdelegate generic_getter(value), do: A
  end
end

defmodule B do
  defstruct [:b]
  def generic_getter(v), do: v.b
  
  defimpl Proto do
    defdelegate generic_getter(value), to: B
  end
end