multiple arrays that must be same length is better represented as array of structs

permit2/src/interfaces/IAllowanceTransfer.sol

Lines 36 to 43 in be76f11

    
           // ERC20 token addresses 
        
           address[] tokens; 
        
           // address permissioned on the allowed tokens 
        
           address spender; 
        
           // the maximum amounts allowed to spend per token 
        
           uint160[] amounts; 
        
           // timestamp at which a spender's token allowances become invalid, assigned per token 
        
           uint64[] expirations;

for readability, this might better be represented as array of structs, something like:

struct Permit {
  address token;
  uint32 nonce;
  uint160 amount;
  uint64 expiry;
}

struct PermitSingle {
  Permit permit;
  address spender;
}

struct PermitBatch {
  Permit[] permits;
  address spender;
}

this structure will also allow passing in a nonce per "permit" for AllowanceTransfer batchPermit

closed with #98

	// ERC20 token addresses
	address[] tokens;
	// address permissioned on the allowed tokens
	address spender;
	// the maximum amounts allowed to spend per token
	uint160[] amounts;
	// timestamp at which a spender's token allowances become invalid, assigned per token
	uint64[] expirations;