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Bonder Contract

Handles bonding of OP20 assets and LP tokens for discounted SLOHM.

Storage​

// Bond info per user
bondPayout: AddressMemoryMap      // SLOHM owed
bondVesting: AddressMemoryMap     // Blocks remaining
bondLastBlock: AddressMemoryMap   // Last interaction

// Global
totalDebt: StoredU256             // Outstanding unvested SLOHM
bcv: StoredU256                   // Bond Control Variable
vestingBlocks: StoredU256         // Default: 720 blocks
lpCaps: AddressMemoryMap          // Max bondable per LP

Key Methods​

bond(asset, amount, maxPrice)​

function bond(asset, amount, maxPrice): void {
    // Verify asset is approved
    require(treasury.isApproved(asset));

    // Check LP cap if applicable
    if (isLP(asset)) {
        require(lpBonded[asset] + amount <= lpCaps[asset]);
    }

    // Pull asset to treasury
    asset.transferFrom(sender, treasury, amount);

    // Calculate value and discount
    const value = isLP(asset) ? calculateRFV(asset, amount) : getAssetValue(asset, amount);
    const price = value × (1 + debtRatio × BCV);
    require(price <= maxPrice, "Slippage");

    // Calculate and record payout
    const payout = value / price;
    bonds[sender].payout += payout;
    bonds[sender].vesting = vestingBlocks;
    totalDebt += payout;
}

claim()​

function claim(): void {
    // Calculate vested amount
    const elapsed = block.number - bond.lastBlock;
    const percentVested = elapsed / bond.vesting;
    const payout = bond.payout × percentVested;

    // Mint vested SLOHM
    Treasury.mintForBond(sender, payout);

    // Update records
    bond.payout -= payout;
    totalDebt -= payout;
}

RFV Calculation​

function calculateRFV(lp, amount): u256 {
    const (reserve0, reserve1) = pool.getReserves();
    const totalLP = lp.totalSupply();
    // RFV = 2 × sqrt(reserve0 × reserve1) × (amount / totalLP)
    return 2 × sqrt(reserve0 × reserve1) × amount / totalLP;
}

View Functions​

  • pendingPayout(user) - Total SLOHM owed
  • claimable(user) - Vested SLOHM available
  • bondPrice(asset) - Current bond price