Rust模块化

Rust模块化

模块化有助于代码的管理和层次逻辑的清晰

Rust模块化有多种方式:

1.嵌套模块

嵌套模块就是直接在要使用模块的文件中声明模块

mod food{//声明模块
   pub struct Cake;
   pub struct Smoothoe;
   pub struct Pizza;
}
use food::Cake;//使用模块中的内容
fn main() {
    let eateable=Cake;
}

2.文件模块

一个.rs文件就是一个和文件同名的模块,在使用的地方要声明模块

file_module/

├── Cargo.toml

└── src

├── food.rs

└── main.rs

food.rs:

   pub struct Cake;
   pub struct Smoothoe;
   pub struct Pizza;

main.rs

mod food;//声明模块
use food::Cake;//使用模块内容
fn main() {
    let eatable=Cake;
}

3.目录模块

2015写法:

dir_module_2015

├── Cargo.toml

└── src

├── food

│ ├── cake.rs

│ ├── mod.rs

│ ├── pizza.rs

│ └── smoothoe.rs

└── main.rs

cake.rs:

pub struct Cake;

pizza.rs

pub struct Pizza;

smoothoe.rs

pub struct Smoothoe;

mod.rs

pub mod cake;
pub mod pizza;
pub mod smoothoe;
use self::cake::Cake;
impl Cake {
    pub fn judge(){
        println!("cake is sweet");
    }
}

main.rs

mod food;
use food::cake::Cake;
fn main() {
    Cake::judge();
}

2018写法：

dir_module_2018

├── Cargo.toml

└── src

├── food

│ ├── cake.rs

│ ├── pizza.rs

│ └── smoothoe.rs

├── food.rs

└── main.rs

cake.rs:

pub struct Cake;

pizza.rs

pub struct Pizza;

smoothoe.rs

pub struct Smoothoe;

food.rs

pub mod cake;
pub mod pizza;
pub mod smoothoe;
use self::cake::Cake;
impl Cake {
    pub fn judge(){
        println!("cake is sweet");
    }
}

main.rs

mod food;
use food::cake::Cake;
fn main() {
    Cake::judge();
}

目前Rust兼容mod.rs写法和文件夹同目录下同名文件写法

导入规则

绝对导入

create:绝对导入前缀,指向当前目的root模块(main.rs或lib.rs)。

相对导入

self:指向于当前模块的元素,用于任何想要引入自身模块所包含的内容时。(例如父模块重新导出子模块 pub use self::cake::Cake; )

super:指向父模块,用于从父模块导入元素。(如果模块bar希望访问副模块foo中的元素Foo,那么可以用super::foo::Foo)