Rust provides a module system that can be used, you can manage your module system in rust with visibility (public/private) between them.
By default, the items in a module in rust have private visibility, and you have a pub keyword to change the visibility module to public.
Okay, let’s try the example, if you have installed rust in your computer, please create new project with command cargo new example-rust-module into your terminal.
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// ./src/main.rs
// to create module in rust you just add keyword mod before statement.
mod example_module {
// can't be accessing from outher, and just work in this current scope.
fn private_function(name: String) -> String {
format!("Hay {}", name)
}
// with pub keyword this function can be access public.
pub fn public_function(name: String) {
println!("{}", private_function(name))
}
}
fn main() {
// Call the example_module
example_module::public_function(String::from("Adiatma")) // output: Hey Adiatma
}
Okay, let’s create a new file with the name another_module.rs.
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// ./src/another_module.rs
mod hello_module {
pub fn hello_func(name: String) {
println!("{}", name)
}
}
And call the module in ./src/main.rs.
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// ./src/main.rs
mod another_module;
fn main() {
another_module::hello_module::hello_func("Adiatma".to_string()); // output: Adiatma
}
How if you want to create a new directory, let’s say mod_dir. and create a new module in mod_dir, to doing it you need to create a file lib.rs in root directory and publish them in lib.rs file, below the example for more detail.
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// ./src/lib.rs
pub mod mod_dir;
And then, in mod_dir you just create the file with name mod.rs.
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// ./mod_dir/mod.rs
pub fn hey(name: String) {
println!("{}", name)
}
Okay, let’s call the module in ./src/main.rs.
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// please add the extern crate keyword and suitable with your project name. example `example_rust_module`.
extern crate example_rust_module;
// add use keyword to call mod `mod_dir`
use example_rust_module::mod_dir;
fn main() {
mod_dir::hey("Adiatma".to_string()); // output: Adiatma
}
Okay, we finish to learning module check this out the repo to read the source code, and if you are curious to learn more about the module in rust please go to https://doc.rust-lang.org/rust-by-example/mod.html.