How to represent shared mutable state?

Question

I\'m trying to learn Rust, but the only thing I do is keep hitting the wall trying to shoehorn familiar (to me) Java concepts into its type system. Or try to shoehorn Haskel

Answer 1

Each Resource can be owned by one Player.

Make the types do that then:

struct Player {
    points: i32,
    resources: Vec,
}

struct Resource {
    gold: i32,
}

fn main() {
    let player1 = Player {
        points: 30,
        resources: vec![Resource { gold: 54 }],
    };
    let player2 = Player {
        points: 50,
        resources: vec![Resource { gold: 99 }],
    };

    // If you really need an array of all the resources...
    // Although this seems like you should just ask the Player to do something
    let mut resources: Vec<_> = vec![];
    resources.extend(player1.resources.iter());
    resources.extend(player2.resources.iter());
}

Edit Thanks to @ziggystar for pointing out my original version allowed players to only have one Resource. Now players may own N resources, but they still are the only owner of a resource.