Pool (ERC-20)

This documentation covers ERC-20 functionality for denominating pool tokens. For Bunicorn Stable-specific functionality, see Pool.

Code

The typical ERC20 functions are inherited from OpenZeppelin's ERC20 token implementation. In addition, the ERC20Permit library containing a permit function for meta-approvals is used.

ERC20Permit.sol

Events

Approval

event Approval(address indexed owner, address indexed spender, uint value);

Emitted each time an approval occurs via approve or permit.

Transfer

event Transfer(address indexed from, address indexed to, uint value);

Emitted each time a transfer occurs via transfer, transferFrom, mint, or burn.

Read-Only Functions

name

function name() external pure returns (string memory);

Return Bunicorn Pool Token (LP token) for each pool.

symbol

function symbol() external pure returns (string memory);

Returns BPT symbol for each pool.

decimals

function decimals() external pure returns (uint8);

Returns 18 for all pools.

totalSupply

function totalSupply() external view returns (uint);

Returns the total amount of BPT tokens for a pool.

balanceOf

function balanceOf(address owner) external view returns (uint);

Returns the amount of BPT tokens owned by an address.

allowance

function allowance(address owner, address spender) external view returns (uint);

Returns the amount of liquidity tokens owned by an address that a spender is allowed to transfer via transferFrom.

DOMAIN_SEPARATOR

function DOMAIN_SEPARATOR() external view returns (bytes32);

Returns a domain separator for use in permit.

PERMIT_TYPEHASH

function PERMIT_TYPEHASH() external view returns (bytes32);

Returns a typehash for use in permit.

nonces

function nonces(address owner) external view returns (uint);

Returns the current nonce for an address for use in permit.

State-Changing Functions

approve

function approve(address spender, uint value) external returns (bool);

Lets msg.sender set their allowance for a spender.

• Emits Approval.

transfer

function transfer(address to, uint value) external returns (bool);

Lets msg.sender send pool tokens to an address.

• Emits Transfer.

transferFrom

function transferFrom(address from, address to, uint value) external returns (bool);

Sends pool tokens from one address to another.

• Requires approval.

• Emits Transfer.

permit

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

Sets the allowance for a spender where approval is granted via a signature.

• Emits Approval.

Interface

pragma solidity 0.6.12;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

interface IERC20Permit is IERC20 {
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;
}