Hello world

Let's write your first Quadrate program.

Your first program

Create a file called hello.qd:

fn main() {
    "Hello, World!" print nl
}

Run it:

quad run hello.qd

Output:

Hello, World!

Breaking it down

The function

fn main() {

• fn declares a function
• main is the entry point (every program needs one)
• () is the stack signature (more on this later)
• { starts the function body

The string

"Hello, World!"

Writing a value pushes it onto the stack. This pushes the string "Hello, World!".

Printing

print

print takes the top value from the stack and prints it.

Newline

nl

nl prints a newline character.

Comments

Use // for single-line comments:

fn main() {
    // This is a comment
    "Hello!" print nl  // This prints a greeting
}

Use /* */ for multi-line comments:

fn main() {
    /*
    This is a
    multi-line comment
    */
    "Hello!" print nl
}

Multiple prints

You can print multiple things:

fn main() {
    "Hello, " print
    "World!" print
    nl
}

Output:

Hello, World!

Printing numbers

Numbers work the same way:

fn main() {
    42 print nl
    3.14 print nl
}

Output:

42
3.14

What's next?

Now that you can print things, let's learn How the Stack Works.