Need an explanation on enum

[EddiePumpin]

Please, I need explanation on RaffleState. I don't understand how it works.

`pragma solidity ^0.8.20;

import "@chainlink/contracts/src/v0.8/vrf/VRFConsumerBaseV2.sol";
import "@chainlink/contracts/src/v0.8/interfaces/VRFCoordinatorV2Interface.sol";
import "@chainlink/contracts/src/v0.8/automation/interfaces/AutomationCompatibleInterface.sol";

error Raffle__NotEnoughETHEntered();
error Raffle__TransferFailed();

contract Raffle is VRFConsumerBaseV2, AutomationCompatibleInterface { // The is keyword in Solidity is used for inheritance, meaning the Raffle contract is inheriting from other contracts or interfaces.
/* Type declaration */
enum RaffleState { // enums can be used to create custom types with a finite set of 'constant values'. By default, OPEN is set to 0 while CALCULATING is set to 1
OPEN,
CALCULATING
}

/* State Variables */
uint256 private immutable i_entranceFee; // immutable' is used when you plan to initialize it later in another function. IMO, we used 'immutable' to reduce the gas cost, since the keyword 'immutable' has been used the has to be resigned.
address payable[] private s_players; // Players have to be in storage because we going to modify it alot and the address will be payable because the players will be paid.
VRFCoordinatorV2Interface private immutable i_vrfCoordinator;
bytes32 private immutable i_gasLane;
uint64 private immutable i_subscriptionId;
uint16 private constant REQUEST_CONFIRMATIONS = 3; // Caps lock and underscore(_) for constant variable.
uint64 private immutable i_callbackGasLimit;
uint32 private constant NUM_WORDS = 1;

// Lottery variables 
address private s_recentWinner;
//bool private s_isOpen; // to true, false
RaffleState private s_rafflestate;

/* Events */
// Event is a convenient way for smart contracts to log data that can be accessed on the Ethereum blockchain. It is used whenever something needs to be updated.
event RaffleEnter(address indexed players); // the nameof the event is usually the reversed of the function name where it wants to be used.
event requestedRandomWinner(uint256 indexed requestId);
event WinnerPicked(address indexed winner);

constructor(
    address vrfCoordinatorV2,
    uint256 entranceFee,
    bytes32 gasLane,
    uint64 subscriptionId,
    uint32 callbackGasLimit
) VRFConsumerBaseV2(vrfCoordinatorV2) {
    //vrfCoordinatorV2 is the address of the contract that does the random number verification.
    i_entranceFee = entranceFee;
    i_vrfCoordinator = VRFCoordinatorV2Interface(vrfCoordinatorV2);
    i_gasLane = gasLane;
    i_subscriptionId = subscriptionId;
    i_callbackGasLimit = callbackGasLimit;
    s_rafflestate = RaffleState.OPEN; // OR RaffleState(0)
}

`

[Nlferu]

Hello @EddiePumpin

An enum (short for "enumeration") in Solidity is a user-defined type that consists of a set of named values. The RaffleState enum has two possible values:

OPEN - Represented by 0
CALCULATING - Represented by 1

These values are used to manage the state of the raffle, ensuring that certain actions can only be performed when the contract is in the correct state. So to sum up it is just custom type created by us you can add more types to define various things like states in contract or input type for Governor votes for example where you have 3 types of votes (FOR - 0, AGAINST - 1, ABSTAIN - 2). It is up to you how many you want to create and when to use which type to track either parameter type or state or whatever use case you find.

[EddiePumpin]

Thanks man