Lesson 8 - Tokenized Votes

The ERC20Votes ERC20 extension

• ERC20Votes properties
• Snapshots
• Creating snapshots when supply changes
• Using snapshots
• Self delegation
• Contract overall operation

References

https://docs.openzeppelin.com/contracts/4.x/api/token/erc20#ERC20Votes

https://docs.openzeppelin.com/contracts/4.x/api/token/erc20#ERC20Snapshot

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/draft-ERC20Permit.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Votes.sol";

contract MyToken is ERC20, ERC20Permit, ERC20Votes {
    constructor() ERC20("MyToken", "MTK") ERC20Permit("MyToken") {}

    // The following functions are overrides required by Solidity.

    function _afterTokenTransfer(address from, address to, uint256 amount)
        internal
        override(ERC20, ERC20Votes)
    {
        super._afterTokenTransfer(from, to, amount);
    }

    function _mint(address to, uint256 amount)
        internal
        override(ERC20, ERC20Votes)
    {
        super._mint(to, amount);
    }

    function _burn(address account, uint256 amount)
        internal
        override(ERC20, ERC20Votes)
    {
        super._burn(account, amount);
    }
}

ERC20Votes and Ballot.sol

• (Review) TDD
• Mapping scenarios
• Contracts structure

Homework

• Read the references
• (Optional) Study how ERC20Permit works https://docs.openzeppelin.com/contracts/4.x/api/token/erc20#ERC20Permit
• (Optional) Study and try out a full governance example from https://docs.openzeppelin.com/contracts/4.x/governance

Weekend project

• Form groups of 3 to 5 students
• Complete the contracts together
• Structure scripts to
  • Deploy everything
  • Interact with the ballot factory
  • Query proposals for each ballot
  • Operate scripts
• Publish the project in Github
• Run the scripts with a few set of proposals, play around with token balances, cast and delegate votes, create ballots from snapshots, interact with the ballots and inspect results
• Write a report detailing the addresses, transaction hashes, description of the operation script being executed and console output from script execution for each step
• (Extra) Use TDD methodology