pattern-match.rs

struct Action {
    _type: String,
    amount: u32
}

fn update_counter(state:u32, action: Action) {
    let Action {_type, amount} = action;
    return match _type.as_ref() {
        "INCREMENT" => state + amount,
        "DECREMENT" => state - amount,
        "RESET" => 0,
        _ => state
    }
}

fn main() {
    let newState = update_counter(4, Action {
        _type: "INCREMENT",
        amount: 2
    });
    
    println!("{}", newState); // 6
}