Week 4: Structs and Enums (Beginner)

Overview

Week 4 introduces Rust’s custom data types: structs and enums. These are Rust’s building blocks for creating rich, type-safe data structures and are comparable to classes and interfaces in JavaScript/TypeScript, but with Rust’s safety guarantees.

Day 1-3: Structs and Methods

Topics

• Defining and instantiating structs
• Field init shorthand
• Struct update syntax
• Tuple structs
• Unit-like structs
• Methods with impl blocks
• Associated functions (like static methods)
• Builder pattern in Rust
• Deriving traits (Debug, Clone, etc.)
• Memory layout of structs

Resources

• Rust Book Ch 5
• Rust By Example: Structs
• Rustlings: Structs exercises
• Memory Layout of Rust Data Types

Use Cases

• Creating domain-specific data types
• Grouping related data together
• Encapsulating data and behavior
• Implementing object-oriented patterns in Rust
• Building reusable components

Day 4-7: Enums, Pattern Matching, Option/Result

Topics

• Defining enums
• Enum variants with data
• Methods on enums
• The Option enum:
  • Some and None variants
  • Replacing null values
• The Result enum:
  • Ok and Err variants
  • Error handling
• Pattern matching with match
• Advanced pattern matching:
  • Destructuring
  • Guards
  • Binding
• The if let syntax
• The while let syntax
• Comparing with TypeScript union types

Resources

• Rust Book Ch 6
• Rust By Example: Enums
• Pattern Matching in Rust
• Option Enum Documentation
• Result Enum Documentation
• Rustlings: Enums exercises

Use Cases

• Representing states and variants
• Handling nullable values safely without null references
• Error handling without exceptions
• Creating type-safe state machines
• Domain modeling with exhaustive pattern matching

Exercises

1. Create a Rectangle struct with width and height fields and methods to calculate area and perimeter
2. Implement a simple Shape enum with variants for different shapes and a method to calculate area
3. Build a simple address book using structs and enums
4. Implement error handling using the Result type
5. Create a program that safely handles optional values using Option
6. Design a state machine using enums and pattern matching

Advanced Challenges

1. Implement a simple vector library with structs and methods
2. Build a configuration parser that handles errors gracefully with Result
3. Create a command-line parser using enums for different commands
4. Design a simplified JSON representation using Rust enums and structs

Next Steps

After completing Week 4, you’ll be able to design custom data types in Rust and handle errors safely using the Option and Result types. Week 5 will expand on error handling and introduce Rust’s collection types.