This Hook provides for a classic xy=k style AMM on an account on Xahau.
- Deposit (remit two currencies)
- Trade (remit one currency)
- Withdrawal (remit no currency)
- Fee voting (XFL LE "FEE" HookParameter when performing a Deposit)
There are no install-time parameters for this Hook, simply install it on an account.
To setup the AMM, Remit two currencies in the ratio that matches the initially desired price. This is the same as a deposit operation. Optionally include a FEE HookParameter on this remit to set your desired AMM fee. This is an XFL LE between 0 and 0.05 (5%).
To deposit liquidity into the AMM Remit the two currencies the AMM contains in the correct ratio. To discover these check the state keys A and B, the data for which is XFL LE. Specifying an XFL LE between 0 and 0.05 as a HookParameter in this remit changes the LP holder's fee vote.
To withdraw send an empty remit. 100% of the LP's share of the two currencies will be remitted back to them. To withdraw less than 100% of the user's LP tokens, submit with HookParameter "WDR" containing the number of LP tokens to liquidate.
To trade against the AMM remit one of the two currencies to receive an emitted remit of the other.
| Parameter | Size | Type | Description |
|---|---|---|---|
| FEE | 8 bytes | XFL LE | Optional fee setting 0-5% (0.00 - 0.05). Default 0.1%. Used for fee voting, during deposit, withdrawal and initial setup |
| WDR | 8 bytes | XFL LE | Optional withdrawal amount in LP tokens. Must be between 1% and 99% of user's existing holdings for partial withdrawals. If omitted then full withdrawal. |
| Key | Size | Type | Description |
|---|---|---|---|
| "CUR" | 80 bytes | Raw bytes | Currency identifiers for pool tokens |
| Bytes 0-39: Currency A (20 bytes currency code + 20 bytes issuer or zeros for XAH) | |||
| Bytes 40-79: Currency B (20 bytes currency code + 20 bytes issuer or zeros for XAH) | |||
| "A" | 8 bytes | XFL LE | Current amount of currency A in pool |
| "B" | 8 bytes | XFL LE | Current amount of currency B in pool |
| "G" | 8 bytes | XFL LE | Geometric mean constant (A×B) |
| "TOT" | 8 bytes | XFL LE | Total LP tokens in circulation |
| "FAC" | 8 bytes | XFL LE | Fee accumulator tracking weighted preferences |
[Account ID] |
16 bytes | XFL LE × 2 | Per-user state |
| Bytes 0-7: User's LP token balance | |||
| Bytes 8-15: User's fee preference |
- XFL LE means XLS-017 in little-endian format.
- XAH (native) amounts are represented with zero-filled issuer and currency fields, but still using XFL.
- All numerical values (amounts, fees, etc.) use the XFL format for consistent mathematical operations
- To retrieve the current fee: divide FAC by the TOT, keeping in mind these are both XFL LE so must be converted to decimal first.