Modules in Rust

Modules are a way to organize code into separate namespaces. They help in managing scope and privacy, making the code more modular and easier to maintain.

Defining a Module

You can define a module using the mod keyword. Here's a basic example:

mod my_module {
    pub fn say_hello() {
        println!("Hello from my_module!");
    }
}

fn main() {
    my_module::say_hello();
}
  • mod my_module defines a module named my_module.
  • pub fn say_hello() defines a public function within the module.
  • my_module::say_hello() calls the function from the main function.

Nested Modules

Modules can be nested within other modules:

mod outer_module {
    pub mod inner_module {
        pub fn say_hello() {
            println!("Hello from inner_module!");
        }
    }
}

fn main() {
    outer_module::inner_module::say_hello();
}
  • pub mod inner_module defines a nested module within outer_module.
  • outer_module::inner_module::say_hello() calls the function from the main function.

Module Files

Modules can also be defined in separate files. For example, you can create a file structure like this:

src/
├── main.rs
└── my_module.rs

In main.rs:

mod my_module;

fn main() {
    my_module::say_hello();
}

In my_module.rs:

pub fn say_hello() {
    println!("Hello from my_module!");
}

This structure helps in keeping the codebase organized and manageable.