Using structs with Access behaviour

coin.ex

# An example struct.
defmodule Coin do
    # Using Kernel.put_in/3 and other methods requires the target to have the Access behaviour.
    @behaviour Access

    # Structs by default do not implement this. It's easy to delegate this to the Map implementation however.
    defdelegate get(coin, key, default), to: Map
    defdelegate fetch(coin, key), to: Map
    defdelegate get_and_update(coin, key, func), to: Map
    defdelegate pop(coin, key), to: Map

    defstruct [:name, :value]
end