# Exchange This is a smart contract to expand ERC-20 that is created with every liquidity pair. The Factory deploys this as new pool creation is requested. Although the Factory actually stores the two tokens of a pair and swapping takes place through it, the Exchange Contract must be called for liquidity to be provided or taken. ## Code Github Link: (Will be updated after official launch) ## Address Contract address after production is deployed ## Events, Read-Only Functions, and State-Changing Functions {% tabs %} {% tab title="Events" %} ## Events #### Transfer ```solidity event Transfer(address indexed from, address indexed to, uint amount); ``` * ERC-20 Standard * Event log of Transfer/Mint/Burn #### Approval ```solidity event Approval(address indexed holder, address indexed spender, uint amount); ``` * ERC-20 Standard * Event log of Approvals #### ChangeMiningRate ```solidity event ChangeMiningRate(uint _mining); ``` * Event log of mining rate change #### ChangeFee ```solidity event ChangeFee(uint _fee); ``` * Event log of trading fee rate changes #### ChangeRateNumerator ```solidity event ChangeRateNumerator(uint rateNumerator); ``` * Event log of rateNumerator changes #### UpdateMiningIndex ```solidity event UpdateMiningIndex(uint lastMined, uint miningIndex); ``` * Event log of pairs’ mining index changes * `lastMined` : Factory.mined() value at the time index is updated * `miningIndex` : pairs’ miningIndex value at the time #### GiveReward ```solidity event GiveReward(address user, uint amount, uint lastIndex, uint rewardSum); ``` * Event log of when mined MESH is claimed and distributed * `user` : address of the user who claimed * `amount` : the amount of MESH claimed * `lastIndex` : index result of the pair of the wallet after claiming * `rewardSum` : The amount of MESH that has been accrued so far #### ExchangePos ```solidity event ExchangePos(address token0, uint amount0, address token1, uint amount1); ``` * Event log of POS transactions * `token0` : Token address delivered by the user * `amount0` : the amount of tokens delivered by the user * `token1` : token address received by user * `amount1` : the amount of tokens received by the user #### ExchangeNeg ``` event ExchangeNeg(address token0, uint amount0, address token1, uint amount1); ``` * Event log of NEG transactions * `token0` : token address delivered by the user * `amount0` : the amount of tokens delivered by the user * `token1` : token address received by the user * `amount1` : the amount of tokens received by the user #### AddLiquidity ``` event AddLiquidity(address user, address token0, uint amount0, address token1, uint amount1, uint liquidity); ``` * Event log of liquidity additions * `liquidity` : the amount of LP tokens minted due to additional liquidity #### RemoveLiquidity ``` event RemoveLiquidity(address user, address token0, uint amount0, address token1, uint amount1, uint liquidity); ``` * Event log of liquidity removals * `liquidity` : the amount of LP tokens burned due to liquidity removal **Sync** ``` event Sync(uint112 reserveA, uint112 reserveB); ``` * Emitted each time reserves are updated. * Parameters * pool : Pool contract address of target pool * reserveA : Token0 liquidity amount * reserveB : Token1 liquidity amount {% endtab %} {% tab title="Read-Only Functions" %} ## Read-Only Functions #### name * Meshswap LP #### symbol * MSLP #### decimals * 18 #### totalSupply * mint/burn depending on liquidity addition/removal #### balanceOf * Number of LP tokens held by each address #### allowance * Status of approval to spender for each address #### factory * The factory address where the LP smart contract is deployed #### token0 * The first token address composed of the pair #### token1 * The second token address composed of the pair **reserve0** * Returns the liquidity quantity of the token0 asset in the current pool **reserve1** * Returns the liquidity quantity of the token1 asset in the current pool #### fee * Transaction fee for the pair * It is a value between 0 and 100, in units of 0.01% * 1 == 0.01%, 100 == 1% #### mining * The mining rate of the pair * It is a value between 0 and 100, in units of 1% * e.g. If mining is 10, the pair has claim authority for 10% of the quantity mined per block in the factory. #### lastMined * Factory.mined() value at the last time the pair updated the index #### miningIndex * Index value of the last recorded pair #### userLastIndex * mapping(address => uint) * Stores the index value at the time of last reward for each user #### userRewardSum * mapping(address => uint ) * Stores the cumulatively claimed MESH quantity value for each user #### getCurrentPool ``` function getCurrentPool() public view returns (uint, uint) ``` * Returns the liquidity quantity of the two assets in the current pool #### estimatePos ``` function estimatePos(address token, uint amount) public view returns (uint) ``` * When a request is made to sell the amount of the corresponding token through a POS transaction, the expected receiving amount of the opposite token is returned. #### estimateNeg ``` function estimateNeg(address token, uint amount) public view returns (uint) ``` * When a request is made to purchase the amount of the corresponding token through a NEG transaction, the expected payment amount of the opposite token is returned. {% endtab %} {% tab title="State-Changing Functions" %} ## State-Changing Functions #### transfer ```solidity function transfer(address _to, uint _value) public returns (bool) ``` * ERC-20 Standard #### transferFrom ```solidity function transferFrom(address _from, address _to, uint _value) public returns (bool) ``` * ERC-20 Standard * Method to transfer tokens on behalf of the approved wallet #### approve ```solidity function approve(address _spender, uint _value) public returns (bool) ``` * ERC-20 Standard * Method to approve transfer as much as value to the spender #### updateMiningIndex ```solidity function updateMiningIndex() public ``` * Method to update the value of the pair contract based on the current Factory.mined() value * Anyone can call in real time. Even if no one calls it, it calls itself if necessary. #### claimReward ``` function claimReward() public ``` * Method that a user calls to claim the claimable MESH that has accumulated for the pair * When called, MESH is claimed from the Factory and paid to `msg.sender` * Even if the method is not called directly, it is automatically called when the LP token balance of the user’s wallet changes. * When liquidity is added * When liquidity is removed * When LP tokens are sent * When LP tokens are received #### addETHLiquidityWithLimit ``` function addETHLiquidityWithLimit(uint amount, uint minAmount0, uint minAmount1, address user) public payable returns (uint real0, uint real1, uint amountLP) ``` * Method used to provide liquidity when token0 is MATIC * Liquidity of the MATIC `msg.value` and token1 `amount` is provided. * After liquidity is provided, the LP token corresponding to the pool share is minted in the `msg.sender` wallet. * If the pair ratio is wrong, as much liquidity as possible is supplied at the current pair ratio, and the remaining tokens are returned to `msg.sender`. * If there is claimable MESH when called, the claim proceeds to `msg.sender`. **addTokenLiquidityWithLimit** ``` function addTokenLiquidityWithLimit(uint amount0, uint amount1, uint minAmount0, uint minAmount1, address user) public nonReentrant returns (uint real0, uint real1, uint amountLP) ``` * Method used to provide liquidity when token0 is MATIC * Liquidity of the MATIC `msg.value` and token1 `amount` is provided. * Set the minimum amount of token0 and token1 to be used for liquidity supply using minAmount0, minAmount1. * After liquidity is provided, the LP token corresponding to the pool share is minted in the `msg.sender` wallet. * If the pair ratio is wrong, as much liquidity as possible is supplied at the current pair ratio, and the remaining tokens are returned to `msg.sender`. * If there is claimable MESH when called, the claim proceeds to `msg.sender`. #### removeLiquidityWithLimitETH ``` function removeLiquidityWithLimitETH(uint amount, uint minAmount0, uint minAmount1, address user) public nonReentrant returns (uint, uint) ``` * Returns the amount of LP tokens, and distributes the corresponding token0 and token1 to the msg.sender wallet * The returned LP token amount is burned * If there is claimable MESH when called, the claim proceeds to msg.sender. **removeLiquidityWithLimit** ``` function removeLiquidityWithLimit(uint amount, uint minAmount0, uint minAmount1, address user) public nonReentrant returns (uint, uint) ``` * Returns the amount of LP tokens, and distributes the corresponding token0 and token1 to the msg.sender wallet * Set the minimum amount for the returned token0 and token1 amounts by using minAmount0, minAmount1. * The returned LP token amount is burned * If there is claimable MESH when called, the claim proceeds to `msg.sender`. {% endtab %} {% endtabs %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.meshswap.fi/developers/contract/exchange.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.