Overview
This lecture explains Rust's most important features, highlighting how they build on ideas from other languages and contribute to Rust's popularity and safety.
Zero-Cost Abstractions
- Rust adopts "zero-cost abstractions" from C++, meaning high-level constructs add no runtime overhead.
- Iterators, generics, and collections in Rust are as efficient as manual loops.
- Rust's Option enum and pattern matching remove undefined behavior, making code safer and more robust.
Ownership and Borrowing
- Rust's ownership model is based on C++'s RAII, tying resource lifetimes to variable scope.
- Only one variable owns a value at a time; when it goes out of scope, the value is dropped.
- Borrowing rules: only one mutable reference or multiple immutable references to a value at any time.
- These rules prevent data races and null pointer dereferencing, ensuring memory and thread safety.
Algebraic Data Types & Pattern Matching
- Rust uses algebraic data types (ADTs) from functional languages (e.g., Haskell) via enums (sum types) and structs (product types).
- Pattern matching is used to handle different enum variants safely and exhaustively.
- ADTs model complex data structures and enforce type-level constraints for safer code.
Traits and Generics (Polymorphism)
- Rust implements polymorphism through traits (like interfaces) and generics.
- Traits define shared behavior; types can implement multiple traits.
- Rust traits are inspired by Haskell's type classes but integrate ownership and borrowing.
- Supports static and dynamic dispatch for flexibility and efficient code.
Async/Await Syntax
- Rust adopts JavaScript's async/await for readable asynchronous programming.
- Async functions in Rust return Futures; execution is lazy (doesn't start until awaited).
- Rust offers true parallelism with multi-threading, unlike JavaScript’s single-threaded event loop.
Macros and Metaprogramming
- Rust macros enable code generation and custom syntax during compilation.
- Macros are hygienic, preventing variable name clashes with surrounding code.
- Declarative macros match patterns and generate code, extending language features.
Package Management (Cargo and Crates.io)
- Rust uses Cargo (build/package manager) and crates.io (package registry), inspired by Node.js's npm.
- Project dependencies are managed in cargo.toml, similar to npm's package.json.
- Cargo simplifies building, testing, and distributing Rust projects.
Key Terms & Definitions
- Zero-cost abstraction — Language feature with no extra runtime cost compared to manual implementation.
- Ownership — Rust's rule tying each value to exactly one variable at a time.
- Borrowing — Temporarily accessing data via references without taking ownership.
- Algebraic Data Type (ADT) — Composite types built from sum (enums) and product (structs) types.
- Trait — Collection of methods that types can implement, similar to interfaces.
- Generic — Code that works with any data type.
- Future — An object representing a value that may not be available yet, used in async programming.
- Macro (hygienic) — Code that generates other code, avoiding naming conflicts.
Action Items / Next Steps
- Practice coding exercises focused on ownership and borrowing.
- Review ADTs, pattern matching, and trait implementation in Rust projects.
- Explore using Cargo for project management and dependency handling.