Modules

In this section we will learn about modules, which are a way to organize code into separate files.

Creating a Module

Every file is a module, but we need to tell the compiler that we want to export some functions from the module.

We can do this using the pub keyword.

src/foo_file.ing

pub fn foo() {
    println!("Hello World!");
}

This will export the function foo from the module foo_file.

We can import a module in the current directory using the mod keyword, and access the specific items using the use keyword.

src/main.ing

use root::foo_file::foo; 

mod foo_file;

fn main() {
    foo();
}

This will import the function foo from the module foo_file, and allow you to use it in the current module.

If the module is in a different folder, you there needs to be a chain of imports.

src/foo_folder/foo_file.ing

pub fn foo() {
    println!("Hello World!");
}

src/foo_folder.ing

mod foo_file

src/main.ing

use root::foo_folder::foo_file::foo; 

mod foo_folder;

fn main() {
    foo();
}

This will import the function foo from the module foo_file in the folder foo_folder.

Notice that a file with the same name as a folder can access all modules inside the folder. This is why we have a foo_folder file and a folder.

This is the way

You can also import multiple items from a module using braces.

src/main.ing

use root::foo_file::{foo, bar}; 

mod foo_file;

fn main() {
    foo();
}

This will import foo and bar from the module foo_file.

You can also import a module with a different name using the as keyword.

src/main.ing

use root::foo_file::{foo, bar as baz}; 

mod foo_file;

fn main() {
    baz();
}

This will import the function foo and bar from the module foo_file, but rename bar as baz. This is useful if there are name collisions.

Last modified: 30 January 2024