dave.exs

defmodule Returning do

  defmacro returning(val, do_block) do
    quote do
      val = unquote(val)
      case val, unquote(do_block)
      val
    end
  end
end

modified.ex

# this won't work
defmodule Returning do
  defmacro returning(val, do_block) do
    quote bind_quoted: [val: val, do_block: do_block] do
      case val, do_block
      val
    end
  end
end