Elixir の require, imoport, use ref: http://qiita.com/taku_oka/items/61178122e7bd52188af1

extoのmodel.ex

  defmacro __using__(_opts) do
    quote do
      use Ecto.Schema
      import Ecto.Changeset
      import Ecto.Query, only: [from: 2]

      import Ecto.Model
      use Ecto.Model.OptimisticLock
      use Ecto.Model.Timestamps
      use Ecto.Model.Dependent
      use Ecto.Model.Autogenerate
      use Ecto.Model.Callbacks
    end
  end

file0.txt

require MyMacros

file1.txt

iex> import List
iex> flatten([1, [2], 3])
[1,2,3]

file2.txt

use HelloPhoenix.Web, :router

file3.txt

use ExUnit.Case, async: true

file4.txt

require ExUnit.Case
ExUnit.Case.__using__([async: true])