Rust/crate

• Rust's unit of compilation — the smallest chunk of code the Rust compiler considers at once

  • Two forms

    • Binary crate — produces a standalone executable; must contain a main function
    • Library crate — produces reusable code to be linked into other crates; the entry point is lib.rs by convention

  • Relationship to packages

    • A package is a Cargo.toml-bounded bundle of one or more crates; "crate" and "package" are often used interchangeably in conversation
    • cargo is the tool that resolves, builds, and manages crate dependencies — see cargo/crate

  • Registry

    • Crates are published to and consumed from crates.io, Rust's official package registry
    • See also Package/Management for the broader pattern

  • Bringing crates into scope

    • Declare a dependency in Cargo.toml, then import items with Rust/use
    • Some items from std are available without any use statement via Rust/prelude

  • Examples in this graph

    • Rust/crate/rand/Rng — the Rng trait from the rand crate
    • Rust/Lib/dotenvy — library crate for .env file loading