Rust Enums and Pattern Matching — Defining Enums, Options, Results, and Match Patterns

DodaTech Updated 2026-06-28 1 min read

In this tutorial, you will learn about Rust Enums and Pattern Matching. We cover key concepts, practical examples, and best practices to help you master this topic.

Rust enums define types with multiple variants using match for exhaustive pattern matching, Option for nullable values, and Result for error handling.

What You'll Learn

Enum definition and variants
Match expressions with patterns
Option and Result enums
if let and while let

Why It Matters

Enums power Rust's error handling and state modeling. DodaZIP uses Result for file operations. Firefox uses enums for HTTP response statuses.

Real-World Use

State machines, error handling, configuration Parsing, network protocol handling.

enum Message {
    Quit,
    Move { x: i32, y: i32 },
    Write(String),
    ChangeColor(i32, i32, i32),
}

impl Message {
    fn call(&self) {
        match self {
            Message::Quit => println!("Quitting"),
            Message::Move { x, y } => println!("Move to {}, {}", x, y),
            Message::Write(text) => println!("Writing: {}", text),
            Message::ChangeColor(r, g, b) => println!("Color: {} {} {}", r, g, b),
        }
    }
}

enum Coin { Penny, Nickel, Dime, Quarter }

fn value_in_cents(coin: Coin) -> u8 {
    match coin {
        Coin::Penny => 1,
        Coin::Nickel => 5,
        Coin::Dime => 10,
        Coin::Quarter => 25,
    }
}

fn main() {
    let msg = Message::Write(String::from("hello"));
    msg.call();

    let some_number = Some(5);
    let absent_number: Option<i32> = None;

    if let Some(value) = some_number {
        println!("Got: {}", value);
    }

    let result: Result<i32, &str> = Ok(42);
    match result {
        Ok(v) => println!("Success: {}", v),
        Err(e) => println!("Error: {}", e),
    }
}

← Previous Rust Structs — Defining, Instantiating, and Implementing Methods on Struct Types Next → Rust Error Handling — Result, Option, Panic, and Error Propagation with ? Operator

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