Last update: September 30, 2021

FranchisedHybridPool

Trident exchange franchised pool template with hybrid like-kind formula for swapping between an ERC-20 token pair.

The reserves are stored as bento shares. However, the stableswap invariant is applied to the underlying amounts. The API uses the underlying amounts.

Functions

constructor

  function constructor(
  ) public

mint

  function mint(
  ) public returns (uint256 liquidity)

Mints LP tokens - should be called via the router after transferring bento tokens. The router must ensure that sufficient LP tokens are minted by using the return value.

burn

  function burn(
  ) public returns (struct IPool.TokenAmount[] withdrawnAmounts)

Burns LP tokens sent to this contract. The router must ensure that the user gets sufficient output tokens.

burnSingle

  function burnSingle(
  ) public returns (uint256 amountOut)

Burns LP tokens sent to this contract and swaps one of the output tokens for another

• i.e., the user gets a single token out by burning LP tokens.

swap

  function swap(
  ) public returns (uint256 amountOut)

Swaps one token for another. The router must prefund this contract and ensure there isn’t too much slippage.

flashSwap

  function flashSwap(
  ) public returns (uint256 amountOut)

Swaps one token for another with payload. The router must support swap callbacks and ensure there isn’t too much slippage.

updateBarFee

  function updateBarFee(
  ) public

Updates barFee for Trident protocol.

_processSwap

  function _processSwap(
  ) internal

_getReserves

  function _getReserves(
  ) internal returns (uint256 _reserve0, uint256 _reserve1)

_updateReserves

  function _updateReserves(
  ) internal

_balance

  function _balance(
  ) internal returns (uint256 balance0, uint256 balance1)

__balance

  function __balance(
  ) internal returns (uint256 balance)

_toAmount

  function _toAmount(
  ) internal returns (uint256 output)

_toShare

  function _toShare(
  ) internal returns (uint256 output)

_getAmountOut

  function _getAmountOut(
  ) internal returns (uint256 dy)

_transfer

  function _transfer(
  ) internal

_computeLiquidity

  function _computeLiquidity(
  ) internal returns (uint256 liquidity)

Get D, the StableSwap invariant, based on a set of balances and a particular A. See the StableSwap paper for details.

Originally https://github.com/saddle-finance/saddle-contract/blob/0b76f7fb519e34b878aa1d58cffc8d8dc0572c12/contracts/SwapUtils.sol#L319.

Return Values:

Name	Type	Description
liquidity	uint256	The invariant, at the precision of the pool.

_computeLiquidityFromAdjustedBalances

  function _computeLiquidityFromAdjustedBalances(
  ) internal returns (uint256 computed)

_getY

  function _getY(
    uint256 x
  ) internal returns (uint256 y)

Calculate the new balances of the tokens given the indexes of the token that is swapped from (FROM) and the token that is swapped to (TO). This function is used as a helper function to calculate how much TO token the user should receive on swap.

Originally https://github.com/saddle-finance/saddle-contract/blob/0b76f7fb519e34b878aa1d58cffc8d8dc0572c12/contracts/SwapUtils.sol#L432.

Parameters:

Name	Type	Description
x	uint256	The new total amount of FROM token.

Return Values:

Name	Type	Description
y	uint256	The amount of TO token that should remain in the pool.

_getYD

  function _getYD(
  ) internal returns (uint256 y)

Calculate the price of a token in the pool given precision-adjusted balances and a particular D and precision-adjusted array of balances.

This is accomplished via solving the quadratic equation iteratively. See the StableSwap paper and Curve.fi implementation for further details. x*1**2 + x1 * (sum’ - (A*n**n - 1) * D / (A _ n**n)) = D ** (n + 1) / (n ** (2 _ n) _ prod’ * A) x_1**2 + b*x_1 = c x_1 = (x_1**2 + c) / (2*x_1 + b) Originally https://github.com/saddle-finance/saddle-contract/blob/0b76f7fb519e34b878aa1d58cffc8d8dc0572c12/contracts/SwapUtils.sol#L276.

Return Values:

Name	Type	Description
y	uint256	The price of the token, in the same precision as in xp.

_handleFee

  function _handleFee(
  ) internal returns (uint256 fee)

_nonOptimalMintFee

  function _nonOptimalMintFee(
  ) internal returns (uint256 token0Fee, uint256 token1Fee)

This fee is charged to cover for swapFee when users add unbalanced liquidity.

getAssets

  function getAssets(
  ) public returns (address[] assets)

getAmountOut

  function getAmountOut(
  ) public returns (uint256 finalAmountOut)

getReserves

  function getReserves(
  ) public returns (uint256 _reserve0, uint256 _reserve1)

Events

Mint

  event Mint(
  )

Burn

  event Burn(
  )

Sync

  event Sync(
  )