Struct MartDriver 

pub struct MartDriver<'a, S: ShopProvider, const N: usize> {
    pub provider: &'a S,
    pub shop_id: S::ShopId,
    pub money: &'a mut u32,
    pub bag: &'a mut Inventory<S::Item, N>,
}

Ready-made MartBackend that routes transactions through the engine’s buy / sell drivers and a ShopProvider.

Suitable for games whose bag is a plain engine Inventory; games with custom bag semantics (overflow spill, key-item rules beyond can_sell, …) implement MartBackend directly.

Fields

provider: &'a S

shop_id: S::ShopId

money: &'a mut u32

bag: &'a mut Inventory<S::Item, N>

Trait Implementations

impl<S: ShopProvider, const N: usize> MartBackend for MartDriver<'_, S, N>

type Item = <S as ShopProvider>::Item

Concrete item identifier type.

fn bag_len(&self) -> usize

Number of occupied bag slots (drives the sell-list cursor).

fn bag_entry(&self, index: usize) -> Option<(S::Item, u8)>

(item, owned_quantity) at bag slot index, if occupied.

fn commit_buy(&mut self, item: S::Item, quantity: u8) -> BuyResult

Commit a purchase of quantity × item: add to the bag and deduct the money. On failure nothing may be mutated.

fn commit_sell(&mut self, bag_index: usize, quantity: u8) -> SellResult

Commit a sale of quantity units of the item at bag_index: remove from the bag and credit the money. On failure nothing may be mutated.

fn can_buy(&self, item: &Self::Item) -> bool

Whether item may be purchased at all (gates entry into the quantity-select phase). Defaults to true.