This contract is a hybrid ERC-404, combining ERC-721 and ERC-20 features. It allows token ownership tracking, ERC-20/ERC-721 transfers, approvals, and EIP-2612 permits. It supports minting/burning, with a queue for banking ERC-721s. It handles ERC-721 exemptions and maintains a dual representation of tokens.

This contract is an ERC404-compliant token with ERC20 and ERC721 features. It allows the owner to set airdrop parameters, mint ERC20 tokens to a recipient, and exempt accounts from ERC721 transfers. It supports token URI generation and airdrop minting for eligible users with valid Merkle proofs.

This contract is a minimal implementation of an ERC404 token, which appears to be a custom token standard. It allows the contract owner to mint ERC20 tokens, optionally mint corresponding ERC721 tokens, set token URIs, and exempt accounts from ERC721 transfers.

The `MockValidERC721Receiver` contract is a minimal implementation of the `ERC721Receiver` interface, which is designed to handle the receipt of ERC721 tokens. This mock contract does not define any custom logic and is likely used for testing purposes to simulate a valid ERC721 token receiver.

This contract is designed to simulate a faulty implementation of the ERC721 token receiver. It incorrectly returns the selector of a non-compliant `wrongSelector` function instead of the correct `onERC721Received` function signature, which would cause ERC721 transfers to fail.

caldereth

0xacme

mathdroid

ERC-404 is an experimental, mixed ERC-20 / ERC-721 implementation with native liquidity and fractionalization. While these two standards are not designed to be mixed, this implementation strives to do so in as robust a manner as possible while minimizing tradeoffs.