Error Handling Patterns

Patterns สำหรับ error handling ใน Rust

Result Basics

fn divide(a: i32, b: i32) -> Result<i32, String> {
    if b == 0 {
        Err("Division by zero".to_string())
    } else {
        Ok(a / b)
    }
}

fn main() {
    // Explicit matching
    match divide(10, 2) {
        Ok(result) => println!("Result: {}", result),
        Err(e) => println!("Error: {}", e),
    }

    // unwrap (panics on Err)
    let result = divide(10, 2).unwrap();
    println!("Unwrap: {}", result);

    // expect (panics with message)
    let result = divide(10, 2).expect("Division failed");
    println!("Expect: {}", result);

    // unwrap_or (default value)
    let result = divide(10, 0).unwrap_or(0);
    println!("With default: {}", result);

    // unwrap_or_else (lazy default)
    let result = divide(10, 0).unwrap_or_else(|e| {
        eprintln!("Error: {}", e);
        -1
    });
    println!("Lazy default: {}", result);

    // is_ok / is_err
    let result = divide(10, 0);
    println!("is_err: {}", result.is_err());
}