imneonizer / How-to-import-nested-modules-in-rust

How to import nested modules in rust.

Rust Nested Imports

Steps to run

chmod +x ./run.sh
bash ./run.sh

• Directory structure:

  src
  ├── foo.rs
  ├── main.rs
  ├── scripts
  │   ├── func.rs
  │   └── mod.rs
  ├── shared
  │   ├── common
  │   │   ├── func.rs
  │   │   └── mod.rs
  │   └── mod.rs
  └── utils
      ├── hello.rs
      ├── mod.rs
      └── world.rs

• The entry point for rust application is src/main.rs it is mandatory to have fn main() inside it.

• Anything that you want to import should first be defined as module

  • As in the main.rs there are four module imports, in other words four modules are defined:

    mod scripts;
    mod utils;
    mod shared;
    mod foo;

  • The three modules scripts, utils, shared are directories while foo is a file.

  • For each module which is a directory, It is mandatory to have mod.rs inside it.

• All functions / sub modules are accessed via :: path separator, eg: foo::init().

• Once the module is defined, It can be used inside any file using same module name, for eg: the file src/shared/common/func.rs is able to use utils::hello::world which is defined at src/utils/hello.rs, pay attention to use keyword for already defined modules.

• Module can also be imported with a different alias to avoid name conflicts, such an example is available inside src/shared/common/func.rs i.e., use scripts::init as scripts_init;

• To use any file present in current file directory of sub module, super keyword can be used, this comes in handy if you don't want to hard code the module directory name. A similar pattern can be notice in python such as from .foo import foo. such an example is available inside src/utils/hello.rs