11. Enums.md

Enums

An enum defines a user-defined type that can be one of several possible variants. Each variant can have its own associated data or be unit-like (containing no data). Enums provide a clear way to express different states or possibilities within your data.

enum Direction {
    North,
    East,
    South,
    West,
}

fn main() {
    let my_direction = Direction::North;
    let new_direction = my_direction; // No error, because Direction is Copy
    move_around(new_direction);
}

fn move_around(direction: Direction) {
    // implements logic to move a character around
}

Benefits of Enums:

• Type Safety: Enums enforce data integrity by restricting values to the defined variants, preventing unexpected types.
• Readability: Enums make code more readable by clearly expressing different states or possibilities within your data.
• Pattern Matching: The match expression provides a powerful way to handle different enum variants concisely.
• Flexibility: Enums can accommodate various data types within variants, offering versatility in data representation.

When to Use Enums:

Consider using enums when you have a set of finite, related possibilities for your data. They are ideal for representing:

• States in a program
• Choices or options
• Error types

Further Learning:

• The Rust Programming Language Book: https://doc.rust-lang.org/book/
• Rust by Example: https://doc.rust-lang.org/book/ch06-01-defining-an-enum.html