# Delegation

Takers may provide allowances on specific offer lists, so other addresses (called "delegate takers") can execute market orders in their name. Allowance may be set using the `approve` function, or through an [EIP712](https://eips.ethereum.org/EIPS/eip-712) permit using the `permit` function.

Allowances are set on a token pair (A, B) without specifying `tickSpacing`, meaning "delegate taker has the right to trade token A against token B at any `tickSpacing`".

## Setting Delegation Allowance

To set allowance, use either the `permit` or `approve` function:

Signature

```solidity
function permit(
    address outbound_tkn,
    address inbound_tkn,
    address owner,
    address spender,
    uint value,
    uint deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
) external;

function approve(
    address outbound_tkn,
    address inbound_tkn,
    address spender,
    uint value
) external returns (bool);
```

### Inputs

#### `permit()`

* `(outbound_tkn, inbound_tkn)` the outbound and inbound tokens of the offer lists on which the `Delegate Taker` will be permitted to execute market orders.
* `owner` the address of the taker providing the permit.
* `spender` the address of the `Delegate Taker`.
* `value` the maximal amount of inbound tokens the `Delegate Taker` is permitted to spend.
* `deadline` the block number beyond which the delegator's signature can no longer be used to obtain permission.
* `(v,r,s)` the `secp256k1` [signature](https://eips.ethereum.org/EIPS/eip-2612) identifying the `owner`.

#### `approve()`

* `(outbound_tkn, inbound_tkn)` the outbound and inbound tokens of the offer lists on which the `Delegate Taker` will be permitted to execute market orders.
* `spender` the address of the `Delegate Taker`.
* `value` the maximal amount of inbound tokens the `Delegate Taker` is permitted to spend.

`msg.sender` is the taker who is approving `spender`.

## Executing Delegated Orders

Once granted, a delegate taker can execute market orders via the `marketOrderFor*` functions:

```solidity
function marketOrderForByTick(
  OLKey memory olKey,
  Tick maxTick,
  uint fillVolume,
  bool fillWants,
  address taker
) external returns (uint takerGot, uint takerGave, uint bounty, uint feePaid);

function marketOrderForByVolume(
    OLKey memory olKey,
    uint takerWants,
    uint takerGives,
    bool fillWants,
    address taker
) external returns (uint takerGot, uint takerGave, uint bounty, uint feePaid);
```

These behave identically to their non-delegated versions, except that the funds and results are attributed to the specified `taker` address.