gistfile1.ex

# lib/my_app.ex

defmodule MyApp do
  import MyApp.Blah
  
  def foo do
    # because we imported it, we can call the `bar` function directly
    bar
  end
end

# lib/my_app/blah.ex

defmodule MyApp.Blah do

  def bar do
    "something"
  end
end

# lib/my_app/qux.ex

defmodule MyApp.Qux do
  def baz do
    # even without importing it, we can still call `bar` if we give the full module path
    MyApp.Blah.bar
  end
end