The Sorting Gate

The simulation is firing mock data logs at your terminal. You must build an iron-clad logic gate to categorize these logs by severity.

1. Defining Choices with Enums

If you use raw text strings to define system states (like "low" or "critical"), a simple typo ("crittical") can crash your entire server. Rust uses enum to enforce strict, predefined choices.

enum Severity {
    Low,
    Critical,
}

2. The Bulletproof Match

Rust provides match, an upgraded version of the traditional if/else block. The compiler forces you to handle every single variant inside an Enum. If you forget to write logic for a Critical alert, your program will refuse to compile. This guarantees you never miss a system failure.

enum Severity {
    Low,
    Critical,
}

fn main() {
    let mock_log = Severity::Critical;

    match mock_log {
        Severity::Low => println!("Log ignored."),
        Severity::Critical => println!("SYSTEM ALERT: Locking down simulation pod!"),
    }
}

Note: Severity::Low and Severity::Critical are variants, not values like strings.

3. Triggering the Gate

What happens if we forget to write logic for the Critical state? Let's break the match block intentionally:

match mock_log {
    Severity::Low => println!("Log ignored."),
    // We deleted the Critical handler!
}

If you attempt to compile this code, Rust physically stops the build process and throws this exact error:

error[E0004]: non-exhaustive patterns: `Severity::Critical` not covered

This strict enforcement guarantees you never miss a system failure. You must handle every possibility.