`rand::distributions::Weighted` is deprecated

[tomassedovic]

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https://docs.rs/rand/0.6.5/rand/distributions/struct.Weighted.html

We use it here:

https://tomassedovic.github.io/roguelike-tutorial/part-12-monster-item-progression.html

Reported via email by Jordan Selanders [email protected] who also sent the following fix:

fn place_objects(room: Rect, map: &Map, objects: &mut Vec<Object>) {
    let num_monsters = rand::thread_rng().gen_range(0, MAX_ROOM_MONSTERS + 1);
    let monster_chances = ["orc", "troll"];
    let monster_weights = [2, 1];
    let monster_dist = WeightedIndex::new(&monster_weights).unwrap();
    let mut rng = rand::thread_rng();
 
    for _ in 0..num_monsters {
        let x = rand::thread_rng().gen_range(room.x1 + 1, room.x2);
        let y = rand::thread_rng().gen_range(room.y1 + 1, room.y2);
 
        let mut monster = match monster_chances[monster_dist.sample(&mut rng)] {
            "orc" => {
                let mut orc = Object::new(x, y, 'o', "orc", colors::DESATURATED_GREEN, true);
                orc.fighter = Some(Fighter {
                    max_hp: 10,
                    hp: 10,
                    defense: 0,
                    power: 3,
                    on_death: DeathCallback::Monster,
                    xp: 10
                });
                orc.ai = Some(Ai::Basic);
                orc
            }
            "troll" => {
                let mut troll = Object::new(x, y, 'T', "troll", colors::DARKER_GREEN, true);
                troll.fighter = Some(Fighter {
                    max_hp: 16,
                    hp: 16,
                    defense: 1,
                    power: 4,
                    on_death: DeathCallback::Monster,
                    xp: 20
                });
                troll.ai = Some(Ai::Basic);
                troll
            }
            _ => unreachable!(),
        };
 
        monster.alive = true;
        objects.push(monster);
    }
 
    let num_items = rand::thread_rng().gen_range(0, MAX_ROOM_ITEMS + 1);
    let item_chances = [Item::Heal, Item::Lightning, Item::Fireball, Item::Confuse];
    let item_weights = [7, 1, 1, 1];
    let item_dist = WeightedIndex::new(&item_weights).unwrap();
 
    for _ in 0..num_items {
        let x = rand::thread_rng().gen_range(room.x1 + 1, room.x2);
        let y = rand::thread_rng().gen_range(room.y1 + 1, room.y2);
 
        if !is_blocked(x, y, map, objects) {
            let mut item = match item_chances[item_dist.sample(&mut rng)] {
                Item::Heal => {
                    let mut object = Object::new(x, y, '!', "healing potion", colors::VIOLET, false);
 
                    object.item = Some(Item::Heal);
                    object
                }
                Item::Lightning => {
                    let mut object = Object::new(x, y, '#', "scroll of lightning bolt", colors::LIGHT_YELLOW, false);
 
                    object.item = Some(Item::Lightning);
                    object
                }
                Item::Fireball => {
                    let mut object = Object::new(x, y, '#', "scroll of fireball", colors::LIGHT_YELLOW, false);
 
                    object.item = Some(Item::Fireball);
                    object
                }
                Item::Confuse => {
                    let mut object = Object::new(x, y, '#', "scroll of confusion",
                                                 colors::LIGHT_YELLOW, false);
 
                    object.item = Some(Item::Confuse);
                    object
                }
            };
 
            item.always_visible = true;
            objects.push(item);
        }
    }
}

[ThibaultLemaire]

Here is the solution I came up with using WeightedIndex when I hit that issue while following the tutorial.