Creating a simple application

In this recipe, we will be using Mix to create a new application.

How to do it…

To create a new Elixir application, follow these steps:

1. In a command-line session, enter mix help to see a list of available tasks:

   > mix help
   

   Here is what the screen will look like:

   
2. To generate a new application, type mix new simple_app:

   > mix new simple_app
   

   What happens next is shown in the following screenshot:

   
3. Inside the simple_app directory, the generated application is ready to be started. Run iex –S mix to start the application and verify that everything is working:

   > iex -S mix
   Erlang/OTP 17 [erts-6.1] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
   Interactive Elixir (0.15.1) - press Ctrl+C to exit (type h() ENTER for help)
   iex(1)>  
   

4. Nothing happened. So is it working? The absence of messages in the IEx session is a good thing. This generated application behaves more like a library; there's no main function like in Java or C. To be sure that the application is responding, edit the lib/simple_app.ex file by inserting the following code:

   defmodule SimpleApp do
     def greet do
       IO.puts "Hello from Simple App!"
     end
   end

5. Restart the application by pressing Ctrl + C twice and entering iex –S mix again.
6. In the IEx session, enter SimpleApp.greet.
7. You will see the following output from the application:

   iex(1)> SimpleApp.greet
   Hello from Simple App!
   :ok
   iex(2)>
   

The Elixir application is ready to be used either on your local machine or, if a node is started, it could even be used from another machine.

How it works…

The Elixir installation provides a command-line tool called Mix. Mix is a build tool. With this tool, it is possible to invoke several tasks to create applications, manage their dependencies, run them, and more.

Mix even allows the creation of custom tasks.

See also

• To generate an OTP application with a supervisor, see the Generating a supervised application recipe.