structs.md

Structs

A struct, or structure, is a custom data type that lets you name and package together multiple related values that make up a meaningful group.

To define a struct, we enter the keyword struct and name the entire struct. A struct’s name should describe the significance of the pieces of data being grouped together. Then, inside curly brackets, we define the names and types of the pieces of data, which we call fields.

Here is an example of a struct in a Phala confidential smart contract

pub struct GhostAuctioneerBot {
    owner: AccountId,
    bot_token: String,
    chat_id: String,
    nft_id: String,
    reserve_price: u64,
    auto_bid_increase: u64,
}

Next lets create an instance of the struct

let ghost_bot = GhostAuctioneerBot {
    owner: contracts::account_id_from_hex(ALICE),
    bot_token: "234819o82:jslkdf9833dklj",
    chat_id: "2813308004",
    nft_id: "9571432-c242166657ef41f61c-LOX47-HUMN-0000000000000004",
    reserve_price: 1,
    auto_bid_increase: 1,
};

Let's change the reserve_price

ghost_bot.reserve_price = 2;

Now we can try another way of defining a GhostAuctioneerBot by passing nft_id, reserve_price, and auto_bid_increase to a function named build_ghost_bot

fn build_ghost_bot(nft_id: String, reserve_price: u64, auto_bid_increase: u64) -> GhostAuctioneerBot {
    GhostAuctioneerBot {
        owner: contracts::account_id_from_hex(ALICE),
        bot_token: "234819o82:jslkdf9833dklj",
        chat_id: "2813308004",
        nft_id: nft_id,
        reserve_price: reserve_price,
        auto_bid_increase: auto_bid_increase,
    }
}

What if we want to create another GhostAuctioneerBot with some values of ghost_bot? Here is how that would work.

let ghost_bot2 = GhostAuctioneerBot {
    owner: ghost_bot.owner,
    bot_token: 1243999:lkajdfhhhhdkfel35,
    chat_id: ghost_bot.chat_id,
    nft_id: "9571432-c242166657ef41f61c-LOX47-HASHWARLOCK-0000000000000001",
    reserve_price: ghost_bot.reserve_price,
    auto_bid_increase: 2,
};