modaug_macro.ex

defmodule MacroM do
  defmacro h_transform(mod) do
    IO.puts "Applying h_transform"
    IO.inspect(mod)
  end

  defmacro la_transform(mod) do
    IO.puts "Applying la_transform"
    IO.inspect(mod)
  end

  defmacro defaugmod(head, body) do
    {
      {:., _, [Kernel, :access]},
      _,
      [
        {:__aliases__, _, [modname]},
        transformers
      ]
    } = head

    quote do
      defmodule unquote(Module.concat([modname])) do
        unquote(body)
      end |> unquote(build_pipe(transformers))
    end
  end

  defp build_pipe([h]) do
    h
  end

  defp build_pipe([h|t]) do
    {:|>, [], [h, build_pipe(t)]}
  end
end

modaug_test.ex

# $ elixir -r modaug_macro.ex modaug_test.ex

import MacroM

defaugmod LAXTester[h_transform, la_transform] do
  def hello do
    "Hello"
  end
end

IO.puts LAXTester.hello