module - 看不懂 Rust 模块系统

Question

我创建了一个用于教育目的的简单项目，所以我有一个主要功能和 3 个特性 Battery、Display 和 GSM 以及实现他们。我希望主要功能位于文件 main.rs 中，而 3 个特征位于另一个名为 phone.rs 的文件中:

phone.rs

mod phone{
    pub struct Battery{
        model : String,
        hours_idle : i16,
        hours_talk : i16
    }

    pub struct Display{
        size : i16,
        number_of_colors : i32
    }

    pub struct GSM{
        model : String,
        manufactor : String,
        price : f32,
        owner : String,
        battery: Battery,
        display : Display
    }

     impl Battery {
        pub fn new(model : String, hours_idle : i16, hours_talk : i16) -> Battery{
            Battery {model : model, hours_idle : hours_idle ,hours_talk : hours_talk}
        }
        pub fn print(&self){
            println!("Battery model: {}", self.model);
            println!("Hours idle: {}", self.hours_idle);
            println!("hours talk: {}", self.hours_talk);
        }
    }

    impl Display {
        pub fn new(size: i16, number_of_colors : i32) -> Display{
            Display{size : size, number_of_colors : number_of_colors}
        }
        pub fn print(&self){
            println!("size: {}", self.size);
            println!("number_of_colors: {}", self.number_of_colors);
        }
    }

     impl GSM {
        pub fn new(model : String, manufactor : String, price : f32, owner : String, battery : Battery, display : Display) -> GSM{
            GSM{model : model, manufactor : manufactor, price : price, owner : owner, battery : battery, display : display }
        }
        pub fn print(&self){
            println!("Model: {}, Manufactor: {}", self.model, self.manufactor);
            println!("price: {}", self.price);
            println!("owner: {}", self.owner);
            self.battery.print();
            self.display.print();
        }
    }
}

ma​​in.rs

pub mod phone;
fn main(){
    let battey = phone::Battery::new("modelBattery".to_string(), 1,2);
    let display =  phone::Display::new(10,20);
    //model : String, manufactor : String, price : f32, owner : String, baterry : Battery, display : Display
    let gsm =  phone::GSM::new("modelPhone".to_string(), "manufactor".to_string(), 100.0, "owner".to_string(), battey, display);
    gsm.print();
}

起初，所有内容都在一个文件 (main.rs) 中并且一切正常(有一些不同，例如我在 Display 前面添加了 phone:: , GSM 和 Battery in main.rs), 当我移动特征并在 phone.rs 中添加 mod phone{} 和 pub mod phone 在 main.rs 中，我从编译器中得到以下错误:

src\main.rs:3:18: 3:37 error: failed to resolve. Could not find `Battery` in `phone` [E0433]
src\main.rs:3     let battey = phone::Battery::new("modelBattery".to_string(), 1,2);
                               ^~~~~~~~~~~~~~~~~~~
src\main.rs:3:18: 3:37 help: run `rustc --explain E0433` to see a detailed explanation
src\main.rs:3:18: 3:37 error: unresolved name `phone::Battery::new` [E0425]
src\main.rs:3     let battey = phone::Battery::new("modelBattery".to_string(), 1,2);
                               ^~~~~~~~~~~~~~~~~~~
src\main.rs:3:18: 3:37 help: run `rustc --explain E0425` to see a detailed explanation
src\main.rs:4:20: 4:39 error: failed to resolve. Could not find `Display` in `phone` [E0433]
src\main.rs:4     let display =  phone::Display::new(10,20);
                                 ^~~~~~~~~~~~~~~~~~~
src\main.rs:4:20: 4:39 help: run `rustc --explain E0433` to see a detailed explanation
src\main.rs:4:20: 4:39 error: unresolved name `phone::Display::new` [E0425]
src\main.rs:4     let display =  phone::Display::new(10,20);
                                 ^~~~~~~~~~~~~~~~~~~
src\main.rs:4:20: 4:39 help: run `rustc --explain E0425` to see a detailed explanation
src\main.rs:6:16: 6:31 error: failed to resolve. Could not find `GSM` in `phone` [E0433]
src\main.rs:6     let gsm =  phone::GSM::new("modelPhone".to_string(), "manufactor".to_string(), 100.0, "owner".to_string(), battey, display);
                             ^~~~~~~~~~~~~~~
src\main.rs:6:16: 6:31 help: run `rustc --explain E0433` to see a detailed explanation
src\main.rs:6:16: 6:31 error: unresolved name `phone::GSM::new` [E0425]
src\main.rs:6     let gsm =  phone::GSM::new("modelPhone".to_string(), "manufactor".to_string(), 100.0, "owner".to_string(), battey, display);
                             ^~~~~~~~~~~~~~~
src\main.rs:6:16: 6:31 help: run `rustc --explain E0425` to see a detailed explanation
src\main.rs:7:5: 7:16 error: the type of this value must be known in this context
src\main.rs:7     gsm.print();

我不明白它们，我在此处和 Google 中进行了搜索，但未能找到解决方案。此外，我收到很多警告，指出 phone.rs 中的方法从未使用过 #[warn(dead_code)]，感谢任何帮助。

Answer 1

简短回答:您不需要 phone.rs 中的 mod phone。只需删除它，您的代码就会工作(假设其余代码是正确的)。

更长的答案:main.rs 中的以下代码:

pub mod phone;

相当于:

pub mod phone {
    // literally insert the contents of phone.rs here
}

因此您不需要将所有内容都包装在 mod phone {} 中的 phone.rs 中。

您当前的代码转换为:

pub mod phone {
    pub mod phone {
        pub struct Battery { ... }
        ...
    }
}

这意味着您需要访问 Battery 作为 phone::phone::Battery (和 Display 作为 phone::phone::Display 等)在 main.rs 中。