Bidding

The Solidity bid flow reads the auction struct, calculates the current price, transfers the NFT, and transfers payment.

Solidity

function bid(uint256 nftId_) external {
    Auction memory auction_ = _auctions[nftId_];
    uint256 price_ = _mustHavePrice(auction_);
    transferFrom(address(this), msg.sender, nftId_);
    auction_.buyToken.transferFrom(msg.sender, address(this), price_);
}

Move

The Move flow operates on an explicit auction object:

entry public fun bid(
    customer: &signer,
    auction: Object<Auction>
) acquires Auction, TokenConfig {
    let auction_address = object::object_address(&auction);
    let auction = borrow_global_mut<Auction>(auction_address);

    let current_price = must_have_price(auction);

    primary_fungible_store::transfer(
        customer,
        auction.buy_token,
        @dutch_auction_address,
        current_price
    );

    let transfer_ref = &borrow_global_mut<TokenConfig>(auction_address).transfer_ref;
    let linear_transfer_ref = object::generate_linear_transfer_ref(transfer_ref);
    object::transfer_with_ref(linear_transfer_ref, signer::address_of(customer));
}

The major migration ideas are:

• bidding targets an object address, not a mapping slot
• payment uses the primary fungible store
• NFT transfer uses object capabilities instead of ERC approval / transfer hooks