Provide a summary for directives

Author: José Valim

getting-started/alias-require-and-import.markdown

@@ -7,7 +7,23 @@ title: alias, require and import
 
 {% include toc.html %}
 
-In order to facilitate software reuse, Elixir provides three directives. As we are going to see below, they are called directives because they have **lexical scope**.
+In order to facilitate software reuse, Elixir provides three directives (`alias`, `require` and `import`) plus a macro called `use` summarized below:
+
+```elixir
+# Alias the module so it can be called as Bar instead of Foo.Bar
+alias Foo.Bar, as: Bar
+
+# Ensure the module is compiled and available (usually for macros)
+require Foo
+
+# Import functions from Foo so they can be called without the `Foo.` prefix
+import Foo
+
+# Invokes the custom code defined in Foo as an extension point
+use Foo
+```
+
+We are going to explore them in detail now. Keep in mind the first three are called directives because they have **lexical scope**, while `use` is a common extension point.
 
 ## `alias`
 
@@ -117,7 +133,42 @@ In the example above, the imported `List.duplicate/2` is only visible within tha
 
 Note that `import`ing a module automatically `require`s it.
 
-## Aliases
+## `use`
+
+Although not a directive, `use` is a macro tightly related to `require` that allows you to use a module in the current context. The `use` macro is frequently used by developers to bring external functionality into the current lexical scope, often modules.
+
+For example, in order to write tests using the ExUnit framework, a developer should use the `ExUnit.Case` module:
+
+```elixir
+defmodule AssertionTest do
+  use ExUnit.Case, async: true
+
+  test "always pass" do
+    assert true
+  end
+end
+```
+
+Behind the scenes, `use` requires the given module and then calls the `__using__/1` callback on it allowing the module to inject some code into the current context. Generally speaking, the following module:
+
+```elixir
+defmodule Example do
+  use Feature, option: :value
+end
+```
+
+is compiled into
+
+```elixir
+defmodule Example do
+  require Feature
+  Feature.__using__(option: :value)
+end
+```
+
+With this we are almost finishing our tour about Elixir modules. The last topic to cover is module attributes.
+
+## Understanding Aliases
 
 At this point you may be wondering: what exactly an Elixir alias is and how is it represented?
 
@@ -152,7 +203,7 @@ iex> mod.flatten([1, [2], 3])
 
 We are simply calling the function `flatten` on the atom `:lists`.
 
-## Nesting
+## Module nesting
 
 Now that we have talked about aliases, we can talk about nesting and how it works in Elixir. Consider the following example:
 
@@ -187,37 +238,3 @@ From Elixir v1.2, it is possible to alias, import or require multiple modules at
 alias MyApp.{Foo, Bar, Baz}
 ```
 
-## `use`
-
-Although not a directive, `use` is a macro tightly related to `require` that allows you to use a module in the current context. The `use` macro is frequently used by developers to bring external functionality into the current lexical scope, often modules.
-
-For example, in order to write tests using the ExUnit framework, a developer should use the `ExUnit.Case` module:
-
-```elixir
-defmodule AssertionTest do
-  use ExUnit.Case, async: true
-
-  test "always pass" do
-    assert true
-  end
-end
-```
-
-Behind the scenes, `use` requires the given module and then calls the `__using__/1` callback on it allowing the module to inject some code into the current context. Generally speaking, the following module:
-
-```elixir
-defmodule Example do
-  use Feature, option: :value
-end
-```
-
-is compiled into
-
-```elixir
-defmodule Example do
-  require Feature
-  Feature.__using__(option: :value)
-end
-```
-
-With this we are almost finishing our tour about Elixir modules. The last topic to cover is module attributes.