Dexter Protocol :: Stable-5-Pool

Dexter's Stable-5-Pool implements the stableswap invariant for upto 5 assets in the pool and implements compute calculations on Liquidity provision / withdrawal and swaps.

Contract State

• Separating Token Accounting and Pool Logic

  The Dexter Pools are responsible only for the math computes which dictate number of tokens to be transferred during swaps / liquidity provisioning events, and do not handle the token transfers themselves. Dexter's Vault queries the Pool contracts to compute how many tokens to transfer and processes those transfers itself.

  This separation simplifies pool contracts, since they no longer need to actively manage their assets; pools only need to calculate amounts for swaps, joins, and exits. Anyone who comes up with a novel idea for a trading system can make a custom pool and have it added to Dexter's PoolType Registery via approval from the Dexter DAO instead of needing to build their own Decentralized Exchange.

Supported Execute Messages

Supported Query Messages

Enums & Structs

MathConfig struct - This struct describes the main math configuration of the stable-pool.

struct MathConfig {
    // This is the current amplification used in the pool
    pub init_amp: u64,
    // This is the start time when amplification starts to scale up or down
    pub init_amp_time: u64,
    // This is the target amplification to reach at `next_amp_time`
    pub next_amp: u64,
    // This is the timestamp when the current pool amplification should be `next_amp`
    pub next_amp_time: u64,
    /// The greatest precision of assets in the pool
    pub greatest_precision: u8,
}

StablePoolUpdateParams enum - This enum stores the options available to start and stop changing a stableswap pool's amplification. Used in the Execute::UpdateConfig function.

enum StablePoolUpdateParams {
    StartChangingAmp { next_amp: u64, next_amp_time: u64 },
    StopChangingAmp {},
}

ResponseType enum - This enum is used to describe if the math computations (joins/exits/swaps) will be successful or not

enum ResponseType {
    Success {},
    Failure (String),
}

Config struct - This struct describes the main control config of pool.

struct Config {
    /// ID of contract which is allowed to create pools of this type
    pub pool_id: Uint128,
    /// The address of the LP token associated with this pool
    pub lp_token_addr: Option<Addr>,
    /// the vault contract address
    pub vault_addr: Addr,
    /// Assets supported by the pool
    pub assets: Vec<Asset>,
    /// The pools type (provided in a [`PoolType`])
    pub pool_type: PoolType,
    /// The Fee details of the pool
    pub fee_info: FeeStructs,
    /// The block time when pool liquidity was last updated
    pub block_time_last: u64,
}

Trade struct - This helper struct is used for swap operations

struct Trade {
    /// The number of tokens to be sent by the user to the Vault
    pub amount_in: Uint128,
    /// The number of tokens to be received by the user from the Vault
    pub amount_out: Uint128,
    /// The spread associated with the swap tx
    pub spread: Uint128,
}

AfterJoinResponse struct - Helper struct for [QueryMsg::OnJoinPool]

struct AfterJoinResponse {
    // Is a sorted list consisting of amount of info of tokens which will be provided by the user to the Vault as liquidity
    pub provided_assets: Vec<Asset>,
    // Is the amount of LP tokens to be minted
    pub new_shares: Uint128,
    // Is the response type :: Success or Failure
    pub response: ResponseType,
    // Is the fee to be charged
    pub fee: Option<Asset>,
}

AfterExitResponse struct - Helper struct for [QueryMsg::OnExitPool]

struct AfterExitResponse {
    /// Assets which will be transferred to the recipient against tokens being burnt
    pub assets_out: Vec<Asset>,
    /// Number of LP tokens to burn
    pub burn_shares: Uint128,
    /// Operation will be a `Success` or `Failure`
    pub response: ResponseType,
    /// Fee to be charged
    pub fee: Option<Asset>,
}

SwapResponse struct - Helper struct for [QueryMsg::OnSwap]

struct SwapResponse {
    ///  Is of type [`Trade`] which contains all params related with the trade
    pub trade_params: Trade,
    /// Operation will be a `Success` or `Failure`
    pub response: ResponseType,
    /// Fee to be charged
    pub fee: Option<Asset>,
}

CumulativePriceResponse struct - Helper struct for [QueryMsg::CumulativePrice]

struct CumulativePriceResponse {
    pub exchange_info: AssetExchangeRate,
    pub total_share: Uint128,
}

CumulativePricesResponse struct - Helper struct for [QueryMsg::CumulativePrices]

struct CumulativePricesResponse {
    pub exchange_info: Vec<AssetExchangeRate>,
    pub total_share: Uint128,
}

Build schema and run unit-tests

cargo schema
cargo test

License

TBD