# SCY Notes

I've added some of those notes here as well: https://www.notion.so/pendle/EIP-XXXX-Super-Composable-Yield-Standard-62d170a68d6f40b286ca88982090b8b7

In summary:
* Need to add the MUST, MAY, SHOULD definitions for each function.
* Do we include 2612 as optional like 4626?
* Do we include 165? Cannot find info why 4626 didn't include it, but it makes so much sense for us to add it.
* Add underlyingToken() to support wrapped implementations mainly, and where it can return zero address if the SCY is a native implementation.
* Should there be preview functions?
* Rename scyIndex() to exchangeRate() to conform with 4626 terminology
* How to explain NoPull effectively to other integrators.
* Do we market the standard as a wrapped standard first? If so, the narrative pivots.
* Need to have SCY implementation example of wrapping an existing 4626 vault.
* Use which math scaling standard for scyIndex? 2^40/1e18/1e27/etc.

Notes from Yaron and William:
* Yaron suggests extending 4626 (since more buy in, but we can't so we need others to understand, might need to mention 4626 in Rationale portion)
* Terminology should be similar to 4626 convention means higher chance of acceptance
* Add veTokens as out of scope
* View/Preview functions CAN BE non-view (in SC perspective to protect against MEV)
* scyIndexCurrent() MAY be view, but we recommend it to be view
* isInvalidBaseToken(), save dev effort to loop through arrays to check, so just implement it

function mintNoPull( // @arun primitive finance is using the same pattern
        address receiver,
        address baseTokenIn,
        uint256 minAmountScyOut
    ) external returns (uint256 amountScyOut);

    function redeemNoPull(
        address receiver,
        address baseTokenOut,
        uint256 minAmountBaseOut
    ) external returns (uint256 amountBaseOut);

    function mint(
        address receiver,
        address baseTokenIn,
        uint256 amountBaseToPull,
        uint256 minAmountScyOut
    ) external returns (uint256 amountScyOut);

    function redeem(
        address receiver,
        address baseTokenOut,
        uint256 amountScyToPull,
        uint256 minAmountBaseOut // recommendation on how to set the min amount (per SCY contract) to avoid manipulation. Pain points: afraid of being frontrun. View function if convenient
    ) external returns (uint256 amountBaseOut);
        
//previewMint and previewRedeem can be non-view ?
        function previewMint( // @arun could be in related periphery contracts ?
        address baseTokenIn,
        uint256 amountBaseToPull
    ) external returns (uint256 amountScyOut);

        function previewRedeem(
        address baseTokenOut,
        uint256 amountScyToPull
    ) external returns (uint256 amountBaseOut);

    
    function updateGlobalRewards() external;
    function updateUserRewards(address user) external;
        // option 1
    function redeemReward(address user) external returns (uint256[] memory outAmounts); // @arun maybe dont separate the redeemRewards into a different function ?

        
        // option 2
    function redeemReward(address to) external returns (uint256[] memory outAmounts);
    
        // scyIndex is always scaled by 1e18
    function scyIndexCurrent() external returns (uint256); // could be view // @arun naming is not standard. Price Per share could be a different name ? Yearn is using it
    function scyIndexStored() external view returns (uint256);
    
    function getBaseTokens() external view returns (address[] memory);
    function isValidBaseToken(address token) external view returns (bool); // saves the efforts/annoyance for looping through the array and check
    function getRewardTokens() external view returns (address[] memory);
    
    // Metadata
    function assetDecimals() external view returns (uint8);
    function assetId() external view returns (bytes32);

## New

interface ISuperComposableYield is IERC20Metadata {
    function mint(
        address receiver,
        address baseTokenIn,
        uint256 amountBaseToPull,
        uint256 minAmountScyOut
    ) external returns (uint256 amountScyOut);

    function redeem(
        address receiver,
        address baseTokenOut,
        uint256 amountScyToPull,
        uint256 minAmountBaseOut
    ) external returns (uint256 amountBaseOut);

    function redeemReward(address user) external returns (uint256[] memory outAmounts);

    /**
    * @notice pricePerAssetCurrent * scyBalance / 1e18 must return the asset balance of the account
    * @notice vice-versa, if a user uses some amount of tokens equivalent to X asset, the amount of scy
    he can mint must be X * pricePerAssetCurrent / 1e18
    * @dev SCYUtils's assetToScy & scyToAsset should be used instead of raw multiplication
    & division
    */
    function pricePerAssetCurrent() external returns (uint256);

    function pricePerAssetStored() external view returns (uint256);

    function getBaseTokens() external view returns (address[] memory);

    function isValidBaseToken(address token) external view returns (bool);

    function getRewardTokens() external view returns (address[] memory);

    function assetDecimals() external view returns (uint8);
}