Enums and Options in Rust

enums.rs

// Allow for rust to recognized unused code
#[!allow(dead_code)]

// Allow rust to be able to debug enum
#[derive(Debug)]
// Direction enum that each type is type of struct (Point) 
enum Direction {
    Up(Point),
    Down(Point),
    Left(Point),
    Right(Point)
}

#[derive(Debug)]

// Keys enum 
enum Keys {
    UpKey(String),
    DownKey(String),
    LeftKey(String),
    RightKey(String)
}


// Create an impl for the enum direction to be able to assign functions to them
// More like a class with methods.
// For each enum you select in the direction enum
// You can match them 
impl Direction {
    fn match_direction(&self) -> Keys {
        match *self {
            Direction::Up(_) => Keys::UpKey(String::from("Pressed w")),
            Direction:: Down(_) => Keys::DownKey(String::from("Pressed s")),
            Direction:: Left(_) => Keys::LeftKey(String::from("Pressed a")),
            Direction:: Right(_) => Keys::RightKey(String::from("Pressed d"))
        }   
    }
}

// Implementation of method relation to the Keys enum
impl Keys {
    fn destruct (&self) -> &String {
        match *self {
            Keys::UpKey(ref s) => s,
            Keys::DownKey(ref s) => s,
            Keys::LeftKey(ref s) => s,
            Keys: RightKey(ref s) => s
        }
    }
}

// Struct Point
#[derive(Debug)]
struct Point {
    x: i32,
    y: i32
}

// Main Bitches!
fn main() {
    let u = Direction::Up(Point { x: 0, y: 1});
    let k = u.match_direction();
    
    println!("{:?}", k);
}

options.rs

// Options take in a genetic type of Some<T> or None
// An example of the division which returns an option of either Some or None
fn division(x: f64, y: f64) -> Option<f64> {
    if y == 0.0 {
        None
    } else {
        Some(x / y)
    }
}


fn main() {
    // assign the option to a variable
    let res = division(10.0, 6.0);
    
    // Match the result to either Some or None
    match res {
        Some(x) => println!("{}", x),
        None => println!("Cannot divide by 0")
    }
}