Adds mint and burn functions

contracts/src/external/Hyperdrive.sol

@@ -244,6 +244,28 @@ abstract contract Hyperdrive is
         _delegate(target4);
     }
 
+    /// Pairs ///
+
+    /// @inheritdoc IHyperdriveCore
+    function mint(
+        uint256,
+        uint256,
+        uint256,
+        IHyperdrive.PairOptions calldata
+    ) external payable returns (uint256, uint256) {
+        _delegate(target4);
+    }
+
+    /// @inheritdoc IHyperdriveCore
+    function burn(
+        uint256,
+        uint256,
+        uint256,
+        IHyperdrive.Options calldata
+    ) external returns (uint256) {
+        _delegate(target4);
+    }
+
     /// Checkpoints ///
 
     /// @inheritdoc IHyperdriveCore

contracts/src/external/HyperdriveTarget0.sol

@@ -10,6 +10,7 @@ import { HyperdriveCheckpoint } from "../internal/HyperdriveCheckpoint.sol";
 import { HyperdriveLong } from "../internal/HyperdriveLong.sol";
 import { HyperdriveLP } from "../internal/HyperdriveLP.sol";
 import { HyperdriveMultiToken } from "../internal/HyperdriveMultiToken.sol";
+import { HyperdrivePair } from "../internal/HyperdrivePair.sol";
 import { HyperdriveShort } from "../internal/HyperdriveShort.sol";
 import { HyperdriveStorage } from "../internal/HyperdriveStorage.sol";
 import { AssetId } from "../libraries/AssetId.sol";
@@ -30,6 +31,7 @@ abstract contract HyperdriveTarget0 is
     HyperdriveLP,
     HyperdriveLong,
     HyperdriveShort,
+    HyperdrivePair,
     HyperdriveCheckpoint
 {
     using FixedPointMath for uint256;

contracts/src/external/HyperdriveTarget1.sol

@@ -8,6 +8,7 @@ import { HyperdriveCheckpoint } from "../internal/HyperdriveCheckpoint.sol";
 import { HyperdriveLong } from "../internal/HyperdriveLong.sol";
 import { HyperdriveLP } from "../internal/HyperdriveLP.sol";
 import { HyperdriveMultiToken } from "../internal/HyperdriveMultiToken.sol";
+import { HyperdrivePair } from "../internal/HyperdrivePair.sol";
 import { HyperdriveShort } from "../internal/HyperdriveShort.sol";
 import { HyperdriveStorage } from "../internal/HyperdriveStorage.sol";
 
@@ -23,6 +24,7 @@ abstract contract HyperdriveTarget1 is
     HyperdriveLP,
     HyperdriveLong,
     HyperdriveShort,
+    HyperdrivePair,
     HyperdriveCheckpoint
 {
     /// @notice Instantiates target1.

contracts/src/external/HyperdriveTarget2.sol

@@ -8,6 +8,7 @@ import { HyperdriveCheckpoint } from "../internal/HyperdriveCheckpoint.sol";
 import { HyperdriveLong } from "../internal/HyperdriveLong.sol";
 import { HyperdriveLP } from "../internal/HyperdriveLP.sol";
 import { HyperdriveMultiToken } from "../internal/HyperdriveMultiToken.sol";
+import { HyperdrivePair } from "../internal/HyperdrivePair.sol";
 import { HyperdriveShort } from "../internal/HyperdriveShort.sol";
 import { HyperdriveStorage } from "../internal/HyperdriveStorage.sol";
 
@@ -23,6 +24,7 @@ abstract contract HyperdriveTarget2 is
     HyperdriveLP,
     HyperdriveLong,
     HyperdriveShort,
+    HyperdrivePair,
     HyperdriveCheckpoint
 {
     /// @notice Instantiates target2.

contracts/src/external/HyperdriveTarget3.sol

@@ -8,6 +8,7 @@ import { HyperdriveCheckpoint } from "../internal/HyperdriveCheckpoint.sol";
 import { HyperdriveLong } from "../internal/HyperdriveLong.sol";
 import { HyperdriveLP } from "../internal/HyperdriveLP.sol";
 import { HyperdriveMultiToken } from "../internal/HyperdriveMultiToken.sol";
+import { HyperdrivePair } from "../internal/HyperdrivePair.sol";
 import { HyperdriveShort } from "../internal/HyperdriveShort.sol";
 import { HyperdriveStorage } from "../internal/HyperdriveStorage.sol";
 
@@ -23,6 +24,7 @@ abstract contract HyperdriveTarget3 is
     HyperdriveLP,
     HyperdriveLong,
     HyperdriveShort,
+    HyperdrivePair,
     HyperdriveCheckpoint
 {
     /// @notice Instantiates target3.

contracts/src/external/HyperdriveTarget4.sol

@@ -8,6 +8,7 @@ import { HyperdriveCheckpoint } from "../internal/HyperdriveCheckpoint.sol";
 import { HyperdriveLong } from "../internal/HyperdriveLong.sol";
 import { HyperdriveLP } from "../internal/HyperdriveLP.sol";
 import { HyperdriveMultiToken } from "../internal/HyperdriveMultiToken.sol";
+import { HyperdrivePair } from "../internal/HyperdrivePair.sol";
 import { HyperdriveShort } from "../internal/HyperdriveShort.sol";
 import { HyperdriveStorage } from "../internal/HyperdriveStorage.sol";
 
@@ -23,6 +24,7 @@ abstract contract HyperdriveTarget4 is
     HyperdriveLP,
     HyperdriveLong,
     HyperdriveShort,
+    HyperdrivePair,
     HyperdriveCheckpoint
 {
     /// @notice Instantiates target4.
@@ -86,6 +88,55 @@ abstract contract HyperdriveTarget4 is
             );
     }
 
+    /// Pairs ///
+
+    // FIXME: Where does this fit?
+    //
+    /// @notice Mints a pair of long and short positions that directly match
+    ///         each other. The amount of long and short positions that are
+    ///         created is equal to the base value of the deposit. These
+    ///         positions are sent to the provided destinations.
+    /// @param _amount The amount of capital provided to open the long. The
+    ///        units of this quantity are either base or vault shares, depending
+    ///        on the value of `_options.asBase`.
+    /// @param _minOutput The minimum number of bonds to receive.
+    /// @param _minVaultSharePrice The minimum vault share price at which to
+    ///        mint the bonds. This allows traders to protect themselves from
+    ///        opening a long in a checkpoint where negative interest has
+    ///        accrued.
+    /// @param _options The pair options that configure how the trade is settled.
+    /// @return maturityTime The maturity time of the new long and short positions.
+    /// @return bondAmount The bond amount of the new long and short positoins.
+    function mint(
+        uint256 _amount,
+        uint256 _minOutput,
+        uint256 _minVaultSharePrice,
+        IHyperdrive.PairOptions calldata _options
+    ) external payable returns (uint256 maturityTime, uint256 bondAmount) {
+        return _mint(_amount, _minOutput, _minVaultSharePrice, _options);
+    }
+
+    // FIXME: Where does this fit?
+    //
+    /// @dev Burns a pair of long and short positions that directly match each
+    ///      other. The capital underlying these positions is released to the
+    ///      trader burning the positions.
+    /// @param _maturityTime The maturity time of the long and short positions.
+    /// @param _bondAmount The amount of longs and shorts to close.
+    /// @param _minOutput The minimum amount of proceeds to receive.
+    /// @param _options The options that configure how the trade is settled.
+    /// @return proceeds The proceeds the user receives. The units of this
+    ///         quantity are either base or vault shares, depending on the value
+    ///         of `_options.asBase`.
+    function burn(
+        uint256 _maturityTime,
+        uint256 _bondAmount,
+        uint256 _minOutput,
+        IHyperdrive.Options calldata _options
+    ) external returns (uint256 proceeds) {
+        return _burn(_maturityTime, _bondAmount, _minOutput, _options);
+    }
+
     /// Checkpoints ///
 
     /// @notice Allows anyone to mint a new checkpoint.

contracts/src/interfaces/IHyperdrive.sol

@@ -200,6 +200,21 @@ interface IHyperdrive is
         bytes extraData;
     }
 
+    struct PairOptions {
+        /// @dev The address that receives the long proceeds from a pair action.
+        address longDestination;
+        /// @dev The address that receives the short proceeds from a pair action.
+        address shortDestination;
+        /// @dev A boolean indicating that the trade or LP action should be
+        ///      settled in base if true and in the yield source shares if false.
+        bool asBase;
+        /// @dev Additional data that can be used to implement custom logic in
+        ///      implementation contracts. By convention, the last 32 bytes of
+        ///      extra data are ignored by instances and "passed through" to the
+        ///      event. This can be used to pass metadata through transactions.
+        bytes extraData;
+    }
+
     /// Errors ///
 
     /// @notice Thrown when the inputs to a batch transfer don't match in

contracts/src/interfaces/IHyperdriveCore.sol

@@ -162,6 +162,47 @@ interface IHyperdriveCore is IMultiTokenCore {
         IHyperdrive.Options calldata _options
     ) external returns (uint256 proceeds, uint256 withdrawalSharesRedeemed);
 
+    /// Pairs ///
+
+    /// @notice Mints a pair of long and short positions that directly match
+    ///         each other. The amount of long and short positions that are
+    ///         created is equal to the base value of the deposit. These
+    ///         positions are sent to the provided destinations.
+    /// @param _amount The amount of capital provided to open the long. The
+    ///        units of this quantity are either base or vault shares, depending
+    ///        on the value of `_options.asBase`.
+    /// @param _minOutput The minimum number of bonds to receive.
+    /// @param _minVaultSharePrice The minimum vault share price at which to
+    ///        mint the bonds. This allows traders to protect themselves from
+    ///        opening a long in a checkpoint where negative interest has
+    ///        accrued.
+    /// @param _options The pair options that configure how the trade is settled.
+    /// @return maturityTime The maturity time of the new long and short positions.
+    /// @return bondAmount The bond amount of the new long and short positoins.
+    function mint(
+        uint256 _amount,
+        uint256 _minOutput,
+        uint256 _minVaultSharePrice,
+        IHyperdrive.PairOptions calldata _options
+    ) external payable returns (uint256 maturityTime, uint256 bondAmount);
+
+    /// @dev Burns a pair of long and short positions that directly match each
+    ///      other. The capital underlying these positions is released to the
+    ///      trader burning the positions.
+    /// @param _maturityTime The maturity time of the long and short positions.
+    /// @param _bondAmount The amount of longs and shorts to close.
+    /// @param _minOutput The minimum amount of proceeds to receive.
+    /// @param _options The options that configure how the trade is settled.
+    /// @return proceeds The proceeds the user receives. The units of this
+    ///         quantity are either base or vault shares, depending on the value
+    ///         of `_options.asBase`.
+    function burn(
+        uint256 _maturityTime,
+        uint256 _bondAmount,
+        uint256 _minOutput,
+        IHyperdrive.Options calldata _options
+    ) external returns (uint256 proceeds);
+
     /// Checkpoints ///
 
     /// @notice Attempts to mint a checkpoint with the specified checkpoint time.

contracts/src/interfaces/IHyperdriveEvents.sol

@@ -102,6 +102,34 @@ interface IHyperdriveEvents is IMultiTokenEvents {
         bytes extraData
     );
 
+    /// @notice Emitted when a pair of long and short positions are minted.
+    event Mint(
+        address indexed longTrader,
+        address indexed shortTrader,
+        uint256 indexed maturityTime,
+        uint256 longAssetId,
+        uint256 shortAssetId,
+        uint256 amount,
+        uint256 vaultSharePrice,
+        bool asBase,
+        uint256 bondAmount,
+        bytes extraData
+    );
+
+    /// @notice Emitted when a pair of long and short positions are burned.
+    event Burn(
+        address indexed trader,
+        address indexed destination,
+        uint256 indexed maturityTime,
+        uint256 longAssetId,
+        uint256 shortAssetId,
+        uint256 amount,
+        uint256 vaultSharePrice,
+        bool asBase,
+        uint256 bondAmount,
+        bytes extraData
+    );
+
     /// @notice Emitted when a checkpoint is created.
     event CreateCheckpoint(
         uint256 indexed checkpointTime,

contracts/src/internal/HyperdriveBase.sol

@@ -29,16 +29,20 @@ abstract contract HyperdriveBase is IHyperdriveEvents, HyperdriveStorage {
     /// @dev Process a deposit in either base or vault shares.
     /// @param _amount The amount of capital to deposit. The units of this
     ///        quantity are either base or vault shares, depending on the value
-    ///        of `_options.asBase`.
-    /// @param _options The options that configure how the deposit is
-    ///        settled. In particular, the currency used in the deposit is
-    ///        specified here. Aside from those options, yield sources can
-    ///        choose to implement additional options.
+    ///        of `_asBase`.
+    /// @param _asBase A flag indicating if the deposit should be made in base
+    ///        or in vault shares.
+    /// @param _extraData Additional data that can be used to implement custom
+    ///        logic in implementation contracts. By convention, the last 32
+    ///        bytes of extra data are ignored by instances and "passed through"
+    ///        to the event. This can be used to pass metadata through
+    ///        transactions.
     /// @return sharesMinted The shares created by this deposit.
     /// @return vaultSharePrice The vault share price.
     function _deposit(
         uint256 _amount,
-        IHyperdrive.Options calldata _options
+        bool _asBase,
+        bytes calldata _extraData
     ) internal returns (uint256 sharesMinted, uint256 vaultSharePrice) {
         // WARN: This logic doesn't account for slippage in the conversion
         // from base to shares. If deposits to the yield source incur
@@ -50,19 +54,16 @@ abstract contract HyperdriveBase is IHyperdriveEvents, HyperdriveStorage {
 
         // Deposit with either base or shares depending on the provided options.
         uint256 refund;
-        if (_options.asBase) {
+        if (_asBase) {
             // Process the deposit in base.
-            (sharesMinted, refund) = _depositWithBase(
-                _amount,
-                _options.extraData
-            );
+            (sharesMinted, refund) = _depositWithBase(_amount, _extraData);
         } else {
             // The refund is equal to the full message value since ETH will
             // never be a shares asset.
             refund = msg.value;
 
             // Process the deposit in shares.
-            _depositWithShares(_amount, _options.extraData);
+            _depositWithShares(_amount, _extraData);
         }
 
         // Calculate the vault share price.
@@ -198,6 +199,23 @@ abstract contract HyperdriveBase is IHyperdriveEvents, HyperdriveStorage {
         }
     }
 
+    /// @dev A yield source dependent check that verifies that the provided
+    ///      pair options are valid. The default check is that the destinations
+    ///      are non-zero to prevent users from accidentally transferring funds
+    ///      to the zero address. Custom integrations can override this to
+    ///      implement additional checks.
+    /// @param _options The provided options for the transaction.
+    function _checkPairOptions(
+        IHyperdrive.PairOptions calldata _options
+    ) internal pure virtual {
+        if (
+            _options.longDestination == address(0) ||
+            _options.shortDestination == address(0)
+        ) {
+            revert IHyperdrive.RestrictedZeroAddress();
+        }
+    }
+
     /// @dev Convert an amount of vault shares to an amount of base.
     /// @param _shareAmount The vault shares amount.
     /// @return baseAmount The base amount.

contracts/src/internal/HyperdriveLP.sol

@@ -55,7 +55,8 @@ abstract contract HyperdriveLP is
         // their contribution was worth.
         (uint256 shareContribution, uint256 vaultSharePrice) = _deposit(
             _contribution,
-            _options
+            _options.asBase,
+            _options.extraData
         );
 
         // Ensure that the contribution is large enough to set aside the minimum
@@ -210,7 +211,8 @@ abstract contract HyperdriveLP is
         // Deposit for the user, this call also transfers from them
         (uint256 shareContribution, uint256 vaultSharePrice) = _deposit(
             _contribution,
-            _options
+            _options.asBase,
+            _options.extraData
         );
 
         // Perform a checkpoint.

contracts/src/internal/HyperdriveLong.sol

@@ -55,7 +55,8 @@ abstract contract HyperdriveLong is IHyperdriveEvents, HyperdriveLP {
         // Deposit the user's input amount.
         (uint256 sharesDeposited, uint256 vaultSharePrice) = _deposit(
             _amount,
-            _options
+            _options.asBase,
+            _options.extraData
         );
 
         // Enforce the minimum user outputs and the minimum vault share price.