dsl.ex

defmodule MacroFun do

  defmacro a(str, do: block) do
    quote do
      { :ok, var!(buffer, MacroFun) } = Agent.start_link fn -> [a: unquote(str)] end
      unquote(block)
      res = Agent.get var!(buffer, MacroFun), &(&1)
      Agent.stop var!(buffer, MacroFun)
      Enum.reverse res
    end
  end

  defmacro b(str) do
    quote do
      Agent.update var!(buffer, MacroFun), &( [ {:b, unquote(str)} | &1 ] )
    end
  end

  defmacro c(str) do
    quote do
      Agent.update var!(buffer, MacroFun), &( [ {:c, unquote(str)} | &1 ] )
    end
  end

end

defmodule Run do
  import MacroFun

  def run do
    res = a "hello" do
      b "blah"
      c "bleh"
    end
    IO.inspect res
  end
end

Run.run