Hello World

This agent prints a message and then stops the ASTRA runtime. This example demonstrates modules, an initial goal and a plan.

Run the example

Use an ASTRA 2.6.1 project from the Quick Start. Save the following code as src/main/astra/Hello.astra.

Hello.astra

agent Hello {
    module Console C;
    module System S;
    initial !init();

    plan +!init() {
        C.println("Hello World");
        S.exit();
    }
}

From the project folder, run:

mvn -Dastra.main=Hello

Expected output

[main]Hello World

The program exits after printing the message.

How it works

The initial goal !init() selects the +!init() plan. The Console module prints the message, and System.exit() stops the entire runtime. Finishing a plan alone does not stop the runtime.

Try a change

Change the greeting, then print a second message before calling exit(). Remove exit() and observe that the runtime stays running; use Ctrl+C to stop it.

See Quick Start and AgentSpeak(L) and ASTRA.