Packages, Crates and Modules

As program grows its importante to group related functionality and group separate code with distict features. Code organization in Rust is done using the concept of packages, crates and modules.

Project code iss split into multiple modules and each module is a separate file. A module is a file that contains one or more items, and the items can be functions, structs, enums, constants, etc.

A package is a collection of crates. A crate is a binary or library that is built using the Rust compiler.

• Packages: A Cargo feature that lets you build, test, and share crates
• Crates: A tree of modules that produces a library or executable, can contain both. This is the primary unit of code organization which can be distributed to the community via crates.io
• Modules and use: Let you control the organization, scope, and privacy of paths
• Paths: A way of naming an item, such as a struct, function, or module

A common practice in the Rust community is to create dual library/binary crates even when the primary intention of a project is to produce an executable.