The Rust Programming Language

Hello, Cargo!

Cargo is Rust’s integrated build system and package manager—equivalent to npm/yarn but with built-in compilation, testing, and project management.

Project Creation

$ cargo new hello_cargo
$ cd hello_cargo

Generated structure:

hello_cargo/
├── Cargo.toml          # Package manifest (like package.json)
├── .gitignore          # Git ignore file
└── src/
    └── main.rs         # Source code

Cargo.toml

[package]
name = "hello_cargo"
version = "0.1.0"
edition = "2024"        # Rust edition (language version)

[dependencies]          # Dependencies (like package.json dependencies)

vs package.json:

• TOML format instead of JSON
• edition field specifies Rust language features
• Dependencies are automatically compiled, not interpreted

Essential Commands

$ cargo build           # Compile (creates target/debug/)
$ cargo run             # Build + execute
$ cargo check           # Type check without generating binary
$ cargo build --release # Optimized build (target/release/)
$ cargo test            # Run tests
$ cargo doc --open      # Generate and open documentation

Development Workflow

Debug builds (default):

• Fast compilation
• Includes debugging symbols
• No optimizations
• Located in target/debug/

Release builds:

• Slower compilation
• Full optimizations
• Smaller binaries
• Located in target/release/

Key Differences from npm/yarn

Cargo.lock

Automatically generated dependency lock file (like package-lock.json). Ensures reproducible builds across environments. Commit to version control for applications, not for libraries.

Integration with Existing Projects

$ git clone <repo>
$ cd <project>
$ cargo build          # Downloads deps, compiles everything

No separate dependency installation step—Cargo handles everything in the build process.

Cargo becomes essential for:

• Dependency management
• Multi-file projects
• Testing and documentation
• Publishing to crates.io (Rust’s package registry)