Yul721.yul is an implementation of the ERC-721 standard for non-fungible tokens (NFTs) in the Yul inline assembly language.
Etherscan does not validate Smart Contracts written in pure Yul. If you want to verify this contract on Etherscan you can use YulSol721.sol which uses Solidity for declaring methods interface.
I've created this project for learning purposes, and it has not been audited for security.
Contract implements a complete ERC721 standard with the following API:
name() and symbol() functions return the name and symbol of the NFT.
balanceOf(address _account) returns the balance of NFTs owned by a specific address.
ownerOf(uint256 _tokenId) returns the owner of a specific token.
mint() allows the creation of a new token. There's a limit of two mints per unique address.
approve(address _to, uint256 _tokenId) allows an address to approve another address to transfer a specific token.
getApproved(uint256 _tokenId) returns the address approved to transfer a specific token.
setApprovalForAll(address _operator, bool _approved) allows an owner to approve or revoke the ability of an operator to manage all their tokens.
isApprovedForAll(address _owner, address _operator) checks if an operator is approved to manage all tokens for a specific owner.
transferFrom(address _from, address _to, uint256 _tokenId) allows the transfer of a specific token from one address to another.
safeTransferFrom(address _from, address _to, uint256 _tokenId, bytes calldata) and safeTransferFrom(address _from, address _to, uint256 _tokenId) provide safe token transfers, checking if the recipient is a contract and calling onERC721Received if needed.