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Lattice

ERC20Permit

Git Source

Inherits: IERC20Permit

Title: ERC20Permit

Author: Modified from OpenZeppelin (https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/extensions/ERC20Permit.sol)

Stateless Diamond facet adding ERC-2612 permit-based approvals to ERC-20.

Owns ONLY the ERC-2612 surface (permit/nonces/DOMAIN_SEPARATOR), implemented over EIP712Lib and NoncesLib. It does NOT inherit the EIP712 / Nonces facets — doing so would re-export eip712Domain() / nonces() and collide with those standalone facets (and any other EIP-712 extension) in a Diamond. A token that also wants ERC-5267 eip712Domain() discovery cuts the standalone EIP712 facet as a COMPONENT via the blueprint (see TokenBlueprintHelper._permitTokenBlueprint); the EIP-712 and nonce storage are seeded once in the token's initializer (EIP712Lib.__EIP712_init/NoncesLib.__Nonces_init). Differences from OpenZeppelin:

  • permit behaves identically.
  • DOMAIN_SEPARATOR stays public view virtual. OpenZeppelin v5.5 dropped virtual (it was already external); the ABI is the same.
  • Registers IERC20Permit for ERC-165 in its init; OpenZeppelin's extension has no ERC-165.

Notes:

  • lattice-version: 0.1.0
  • lattice-source: OpenZeppelin v5.6.1

Functions

permit

Sets value as the allowance of spender over owner's tokens, given a signed approval.

function permit(address owner, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s)
        public
        virtual;

Parameters

NameTypeDescription
owneraddress
spenderaddress
valueuint256
deadlineuint256
vuint8
rbytes32
sbytes32

nonces

Returns the current nonce for owner (for use in permit signatures).

function nonces(address owner) public view virtual returns (uint256);

Parameters

NameTypeDescription
owneraddress

Returns

NameTypeDescription
<none>uint256

DOMAIN_SEPARATOR

Returns the domain separator used in the encoding of permit signatures.

function DOMAIN_SEPARATOR() public view virtual returns (bytes32);

Returns

NameTypeDescription
<none>bytes32

exportSelectors

ERC-8153 selector export: this facet's cuttable selectors, tightly packed (4 bytes each).

Excludes exportSelectors() itself (0x0ef22643) - it is never cut into a diamond. Order matches forge inspect ERC20Permit methodIdentifiers (alphabetical by signature); kept in exact parity by ExportSelectorsParityTest. Chunks: DOMAIN_SEPARATOR() 0x3644e515 nonces(address) 0x7ecebe00 permit(address,address,uint256,uint256,uint8,bytes32,bytes32) 0xd505accf

 
function exportSelectors() external pure virtual returns (bytes memory selectors);

Returns

NameTypeDescription
selectorsbytes