Learning to use the Combine parser combinator library for Elixir by implementing a US phone number parser.
$ asdf install
$ mix deps.get
$ iex -S mix
iex> PhoneNumber.parse("+1 (123) 456-7890")
%PhoneNumber{country_code: 1, area_code: 123, subscriber_number: "456-7890"}
iex> PhoneNumber.test()