Hello World

Let’s write your first Ferret program!

Create a File

Create a file named main.fer in your project directory (folder).:

run

// Your first Ferret program
import "std/io";

fn main() {
    let greeting: str = "Hello, World!";
    io::Println(greeting);
}

Run the Program

Compile and run your program:

ferret main.fer

The compiler will produce a little program of the same name as your current project folder. So if your project folder is named hello, you’ll get an executable named hello (or hello.exe on Windows). Run it like this:

./hello # On Windows, use: ./hello.exe

Or compile with a custom output name:

ferret -o myapp hello.fer
./myapp

Understanding the Code

Let’s break down what’s happening:

• fn main() - Every Ferret program starts with a main function
• let greeting: str = "Hello, World!"; - Declares a variable with type annotation
• io::Println(greeting); - Outputs the greeting to the console

Try It Yourself

Try modifying the program:

run

import "std/io";

fn greet(name: str) -> str {
    return "Hello, " + name + "!";
}

fn main() {
    let name: str = "Ferret";
    let message: str = greet(name);
    io::Println(message);
}

Next Steps

• Learn about Variables & Constants
• Explore the Type System
• Understand Functions