Actr

Macros for more concise GenServers

Why?

Sometimes I just want to write one definition and see all my GenServer functionality in a single 24-line page. Sometimes I just want to see my public API signature and my private API signature side by side. Sometimes I'm just lazy.

Usage

Mind you, even the trival example below outputs warnings about function clauses not being grouped properly. I plan to later collect all the clauses into different module attributes, then output the contents of each group.

Alternatively, I could just apply the given functions inside a single handle_call or handle_cast, but then the default GenServer implementations will never be called.

defmodule TestServer do
  use Actr

  require Logger

  # Define public API
  defcast update(new_value)
      when is_binary(new_value),
  fn
    # Define private API
    ({:update, "magic"}, state) ->
      {:noreply, %{state|value: "Huzzah!"}}

    # Define private API
    ({:update, new_value}, state)
        when is_binary(new_value)
    ->
      Logger.info "You didn't say the magic word"

      {:noreply, %{state|value: new_value}}
  end

  # Define public API
  defcast notify, fn
    # Define private API
    (:notify, state) ->
      Logger.info "Got notification"

      {:noreply, state}
  end

  # Define public API
  defcall get(:status), fn
    # Define private API
    ({:get, :status}, _from, state) ->
      {:reply, {:ok, state.value}, state}
  end

  # Define public API
  defcall status, fn
    # Define private API
    (:status, _from, state) ->
      {:reply, {:ok, state.value}, state}
  end

  # No `definfo` macro, because what would be the point?
  #
  @impl true
  def handle_info({:snap, from}, state) do
    send(from, "Snap!")

    {:noreply, state}
  end

  # Define public API
  deflink start_link(initial \\ "stuff"), fn
    # Define private API
    [arg] ->
        {:ok, %{value: arg}}
  end
end

Installation

def deps do
  [ { :actr_ex,
      git: "https://gitlab.com/jonnystorm/actr-elixir.git"
    },
  ]
end