Exprotobuf - Prototyping the use of :gpb.compile/2

exprotobuf.ex

defmodule Protobuf do
  # alias Protobuf.Parser
  # alias Protobuf.Builder
  # alias Protobuf.Config
  # alias Protobuf.ConfigError
  # alias Protobuf.Field
  # alias Protobuf.OneOfField
  # alias Protobuf.Utils
  alias Mix.Compilers.Erlang

  defmacro __using__(opts) do
    path = Path.expand(opts[:path])
    if File.exists?(path) do
      IO.puts "Compiling proto from proto: #{path}"
      IO.inspect :gpb_compile.file('user.proto', [{:i, '/app/lib'}, :mapfields_as_maps])
      # erl_file = Erlang.to_erl_file("/app/user.erl")
      # IO.inspect erl_file
      compiled = :compile.file('/app/user.erl', [{:i, '_build/dev/lib/gpb/include'}])
      IO.inspect compiled
    end

    quote do
      require Record
      import Record, only: [defrecord: 2, extract: 2]
      defrecord :user, extract(:User, from: "user.hrl")
      def encode(data), do: :user.encode_msg(data)
      def decode(bin), do: :user.decode_msg(bin, :User)
    end
  end
end

# Teste:
User.encode({:User, "abc", %{"def" => "x123", "ghi" => "y456"}}) |> User.decode