Clarification on Elixir Mix Run Behavior for IO.puts

The discussion revolves around an issue encountered by an Elixir developer named Slavjuan, who observed that `IO.puts` statements in a module only output to the console on the first execution of `mix run`. Community members explained that Elixir code placed at the top level is executed at compile time, hence why subsequent `mix run` executions without changes to the code don't result in the `IO.puts` being executed again. To ensure the `IO.puts` executes every time at runtime, Sentreen advised running the function in the Elixir interactive shell (iex) or placing the code into a script file (.exs). There's also a clarification that using `mix compile` and `mix run` differs when requiring runtime execution, and to achieve consistent application execution, the code should implement the Application behavior with a `start` function. Discussions also touched upon metaprogramming and the specific concept of 'application' within Erlang/Elixir which implies a long-running process that responds to input, as explained by other community members contributing to the thread.