HelloWorld

As tradition dictates, we will start by writing a simple HelloWorld program. Orb source files have the extension .orb. Here is the main.orb file containing the code:

import "std/io.orb";

fnc main () () {
    std.println "Hello, world!";
};

Let’s dissect all that’s happening here. First, we import std/io.orb from the standard library. This file contains various definitions for reading from the standard input and writing to the standard output.

Then we define a main function, using the fnc special form. This function is the entry point to our program. There are a few different signatures it may have, but here it simply takes no arguments and returns no values.

Inside its body, we invoke std.println to output a string, followed by a newline character.

To compile and execute this program, run these commands from the same directory that contains main.orb (it is assumed you have orbc installed on your system):

orbc main.orb
./main

When the program executes, you should see Hello, world! printed to the console.

Congratulations, you wrote your first Orb program! Click next to proceed to the next lesson.