package

• src/main.rs 是crate的默认约定入口, 或者src/lib.rs
• 一个package由一个或多个crate组成
• 二进制程序，或者lib 库

$ cargo new my-project
     Created binary (application) `my-project` package
$ ls my-project
Cargo.toml
src
$ ls my-project/src
main.rs

modules

mod front_of_house {
    mod hosting {
        fn add_to_waitlist() {}

        fn seat_at_table() {}
    }

    mod serving {
        fn take_order() {}

        fn serve_order() {}

        fn take_payment() {}
    }
}

mod的例子

mod front_of_house {
    mod hosting {
        fn add_to_waitlist() {}

        fn seat_at_table() {}
    }

    mod serving {
        fn take_order() {}

        fn serve_order() {}

        fn take_payment() {}
    }
}

• use
  引入外部库/系统库到当前crate
• pub
  让当前module、方法对外可见