ERC 20 Votes

Extension of ERC20 to support Compound-like voting and delegation. This version is more generic than Compound's, and supports token supply up to 2^224^ - 1, while COMP is limited to 2^96^ - 1. NOTE: If exact COMP compatibility is required, use the {ERC20VotesComp} variant of this module. This extension keeps a history (checkpoints) of each account's vote power. Vote power can be delegated either by calling the {delegate} function directly, or by providing a signature to be used with {delegateBySig}. Voting power can be queried through the public accessors {getVotes} and {getPastVotes}. By default, token balance does not account for voting power. This makes transfers cheaper. The downside is that it requires users to delegate to themselves in order to activate checkpoints and have their voting power tracked. Enabling self-delegation can easily be done by overriding the {delegates} function. Keep in mind however that this will significantly increase the base gas cost of transfers. Available since v4.2.

Methods

DOMAIN_SEPARATOR

function DOMAIN_SEPARATOR() external view returns (bytes32)

See {IERC20Permit-DOMAIN_SEPARATOR}.

Returns

Name	Type	Description
_0	bytes32	undefined

allowance

function allowance(address owner, address spender) external view returns (uint256)

See {IERC20-allowance}.

Parameters

Name	Type	Description
owner	address	undefined
spender	address	undefined

Returns

Name	Type	Description
_0	uint256	undefined

approve

function approve(address spender, uint256 amount) external nonpayable returns (bool)

See {IERC20-approve}. Requirements: - spender cannot be the zero address.

Parameters

Name	Type	Description
spender	address	undefined
amount	uint256	undefined

Returns

Name	Type	Description
_0	bool	undefined

balanceOf

function balanceOf(address account) external view returns (uint256)

See {IERC20-balanceOf}.

Parameters

Name	Type	Description
account	address	undefined

Returns

Name	Type	Description
_0	uint256	undefined

checkpoints

function checkpoints(address account, uint32 pos) external view returns (struct ERC20Votes.Checkpoint)

Get the pos-th checkpoint for account.

Parameters

Name	Type	Description
account	address	undefined
pos	uint32	undefined

Returns

Name	Type	Description
_0	ERC20Votes.Checkpoint	undefined

decimals

function decimals() external view returns (uint8)

Returns the number of decimals used to get its user representation. For example, if decimals equals 2, a balance of 505 tokens should be displayed to a user as 5.05 (505 / 10 ** 2). Tokens usually opt for a value of 18, imitating the relationship between Ether and Wei. This is the value {ERC20} uses, unless this function is overridden; NOTE: This information is only used for display purposes: it in no way affects any of the arithmetic of the contract, including {IERC20-balanceOf} and {IERC20-transfer}.

Returns

Name	Type	Description
_0	uint8	undefined

decreaseAllowance

function decreaseAllowance(address spender, uint256 subtractedValue) external nonpayable returns (bool)

Atomically decreases the allowance granted to spender by the caller. This is an alternative to {approve} that can be used as a mitigation for problems described in {IERC20-approve}. Emits an {Approval} event indicating the updated allowance. Requirements: - spender cannot be the zero address. - spender must have allowance for the caller of at least subtractedValue.

Parameters

Name	Type	Description
spender	address	undefined
subtractedValue	uint256	undefined

Returns

Name	Type	Description
_0	bool	undefined

delegate

function delegate(address delegatee) external nonpayable

Delegate votes from the sender to delegatee.

Parameters

Name	Type	Description
delegatee	address	undefined

delegateBySig

function delegateBySig(address delegatee, uint256 nonce, uint256 expiry, uint8 v, bytes32 r, bytes32 s) external nonpayable

Delegates votes from signer to delegatee

Parameters

Name	Type	Description
delegatee	address	undefined
nonce	uint256	undefined
expiry	uint256	undefined
v	uint8	undefined
r	bytes32	undefined
s	bytes32	undefined

delegates

function delegates(address account) external view returns (address)

Get the address account is currently delegating to.

Parameters

Name	Type	Description
account	address	undefined

Returns

Name	Type	Description
_0	address	undefined

getPastTotalSupply

function getPastTotalSupply(uint256 blockNumber) external view returns (uint256)

Retrieve the totalSupply at the end of blockNumber. Note, this value is the sum of all balances. It is but NOT the sum of all the delegated votes! Requirements: - blockNumber must have been already mined

Parameters

Name	Type	Description
blockNumber	uint256	undefined

Returns

Name	Type	Description
_0	uint256	undefined

getPastVotes

function getPastVotes(address account, uint256 blockNumber) external view returns (uint256)

Retrieve the number of votes for account at the end of blockNumber. Requirements: - blockNumber must have been already mined

Parameters

Name	Type	Description
account	address	undefined
blockNumber	uint256	undefined

Returns

Name	Type	Description
_0	uint256	undefined

getVotes

function getVotes(address account) external view returns (uint256)

Gets the current votes balance for account

Parameters

Name	Type	Description
account	address	undefined

Returns

Name	Type	Description
_0	uint256	undefined

increaseAllowance

function increaseAllowance(address spender, uint256 addedValue) external nonpayable returns (bool)

Atomically increases the allowance granted to spender by the caller. This is an alternative to {approve} that can be used as a mitigation for problems described in {IERC20-approve}. Emits an {Approval} event indicating the updated allowance. Requirements: - spender cannot be the zero address.

Parameters

Name	Type	Description
spender	address	undefined
addedValue	uint256	undefined

Returns

Name	Type	Description
_0	bool	undefined

name

function name() external view returns (string)

Returns the name of the token.

Returns

Name	Type	Description
_0	string	undefined

nonces

function nonces(address owner) external view returns (uint256)

See {IERC20Permit-nonces}.

Parameters

Name	Type	Description
owner	address	undefined

Returns

Name	Type	Description
_0	uint256	undefined

numCheckpoints

function numCheckpoints(address account) external view returns (uint32)

Get number of checkpoints for account.

Parameters

Name	Type	Description
account	address	undefined

Returns

Name	Type	Description
_0	uint32	undefined

permit

function permit(address owner, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) external nonpayable

See {IERC20Permit-permit}.

Parameters

Name	Type	Description
owner	address	undefined
spender	address	undefined
value	uint256	undefined
deadline	uint256	undefined
v	uint8	undefined
r	bytes32	undefined
s	bytes32	undefined

symbol

function symbol() external view returns (string)

Returns the symbol of the token, usually a shorter version of the name.

Returns

Name	Type	Description
_0	string	undefined

totalSupply

function totalSupply() external view returns (uint256)

See {IERC20-totalSupply}.

Returns

Name	Type	Description
_0	uint256	undefined

transfer

function transfer(address recipient, uint256 amount) external nonpayable returns (bool)

See {IERC20-transfer}. Requirements: - recipient cannot be the zero address. - the caller must have a balance of at least amount.

Parameters

Name	Type	Description
recipient	address	undefined
amount	uint256	undefined

Returns

Name	Type	Description
_0	bool	undefined

transferFrom

function transferFrom(address sender, address recipient, uint256 amount) external nonpayable returns (bool)

See {IERC20-transferFrom}. Emits an {Approval} event indicating the updated allowance. This is not required by the EIP. See the note at the beginning of {ERC20}. Requirements: - sender and recipient cannot be the zero address. - sender must have a balance of at least amount. - the caller must have allowance for sender's tokens of at least amount.

Parameters

Name	Type	Description
sender	address	undefined
recipient	address	undefined
amount	uint256	undefined

Returns

Name	Type	Description
_0	bool	undefined

Events

Approval

event Approval(address indexed owner, address indexed spender, uint256 value)

Parameters

Name	Type	Description
owner indexed	address	undefined
spender indexed	address	undefined
value	uint256	undefined

DelegateChanged

event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate)

Emitted when an account changes their delegate.

Parameters

Name	Type	Description
delegator indexed	address	undefined
fromDelegate indexed	address	undefined
toDelegate indexed	address	undefined

DelegateVotesChanged

event DelegateVotesChanged(address indexed delegate, uint256 previousBalance, uint256 newBalance)

Emitted when a token transfer or delegate change results in changes to an account's voting power.

Parameters

Name	Type	Description
delegate indexed	address	undefined
previousBalance	uint256	undefined
newBalance	uint256	undefined

Transfer

event Transfer(address indexed from, address indexed to, uint256 value)

Parameters

Name	Type	Description
from indexed	address	undefined
to indexed	address	undefined
value	uint256	undefined