Modules

Modules allow creating individual scopes and organise your code better. Read about modules in cairo book.

Here's some code to show modules at play,

Declaring modules

Modules can be declared in two ways,

Code	Description
mod filename;	Module from a filename.cairo
mod { ... }	Inline module code in braces

In the exercises we'll use inline modules, but the behaviour is identical.

lib.cairo

// Module from a file
mod restaurant;

fn main() {
	// ...
}

restaurant.cairo

fn add_to_waitlist() {}
fn seat_at_table() {}

// Inline modules
mod serving {
    fn take_order() {}
    fn serve_order() {}
}

mod checkout {
    fn get_bill() {}
    fn collect_payment() {}
}

Using stuff in modules

Keyword	Description	Example
super	Access parent scope	super::my_module::my_fn
use	Create shortcuts	use my_module::my_fn

lib.cairo

// ...
use restaurant::seat_at_table; // Creates shortcut to seat_at_table
use restaurant::serving::serve_order; // Another shortcut
use restaurant::checkout; // Shortcut to a module


fn main() {
	restaurant::add_to_waitlist();
	seat_at_table(); // Shortcut thanks to use

	restaurant::serving::take_order();
	serve_order(); // Via shortcut
}

mod cutomer_checkout {
	fn start() {
		super::checkout::collect_payment();
	}
}