Using module directives

To simplify working with modules, Elixir provides three directives: import, alias, and require. These three module directives are lexically scoped—if defined in the module scope, they are valid for the whole module, but if defined inside a function, they are only valid inside that function.

These three directives allow the use of code defined in other modules.

Getting ready

Create the require_me.ex file with the following content:

defmodule RequireMe do
  def foo do
    IO.puts "This is foo from #{__MODULE__} module"
  end
end

In the same folder, create the directives.ex file and add the following code:

defmodule Directives do
  @col  [1,2,3]
  @name "demo"

  # require directive

  # alias directive module scope
  alias String, as: S
  # import directive module scope
  import List, only: [first: 1]

  def test_module_alias do
    IO.puts "Name is #{S.capitalize(@name)}"
  end

  def test_function_alias do
    # alias directive function scope
    alias RequireMe, as: RM...