GenServer macros

genserver_interface.ex

defmodule GenServer.Interface do

  defmacro defcall(function, arity) do
    args = for n <- :lists.seq(1,arity), do: {"arg" <> Integer.to_string(n) |> String.to_atom, [], Elixir}
    quote do
      def unquote(function)(server, unquote_splicing(args)) do
        GenServer.call(server, {unquote(function), unquote_splicing(args)})
      end
    end
  end

  defmacro defcast(function, arity) do
    args = for n <- :lists.seq(1,arity), do: {"arg" <> Integer.to_string(n) |> String.to_atom, [], Elixir}
    quote do
      def unquote(function)(server, unquote_splicing(args)) do
        GenServer.cast(server, {unquote(function), unquote_splicing(args)})
      end
    end
  end
  
end

Usage:

defmodule StateServer do
  use GenServer
  import GenServer.Interface

  defcall get_state, 0
  defcall set_state, 1

  ...
end

generates:

def get_state(server) do
    GenServer.call(server, {:get_state})
end

def set_state(server, arg1) do
    GenServer.call(server, {:get_state, arg1})
end