A simple Sui Move version AMM Dex based on the logic of UniswapV2. ## Introduction + This module implements the factory and pool logic of UniswapV2 where anyone can freely create pair of two coin types, add or remove liquidity, and swap. + After a `Pool` of two coin types is created, a `PoolItem` will be added to `Factory`'s `table` field, which guarantees there is at most one pool for a pair. + The two coin types of a pair are first sorted according to their `type_name`, and then assigned to `PoolItem`'s `a` and `b` fields respectively. + Users can add liquidity to the pool according to the current ratio of coin balances. The remaining coin will be returned to the users as well as the LP coin. + Each pool are set with a `0.3%` swap fee by default which is actually distributed to all LP holders. + Core functions like `create_pool`, `add_liquidity`, `remove_liquidity`, `swap_a_for_b`, `swap_b_for_a` are all provided with three kind of interfaces (call with `Balance`, call with `Coin` and return `Coin`, call with `Coin` and transfer the output `Coin` to the sender in that entry function) considering both composability and convenience. ## Structs 1. LP witness + LP witness `LP<A, B>` is used as unique identifier of `Coin<LP<A, B>>` type. 2. Pool + A `Pool<A, B>` is a global shared object that is created by the one who calls the `create_pool` function. + It records its `Balance<A>`, `Balance<B>`, `Supply<LP<A, B>>`, and default fee. 3. Factory + A `Factory` is a global shared object that is created only once during the package publishment. + It has a `table` field recording each `PoolItem`. 4. PoolItem + A `PoolItem` is used to record the pool info in the `Factory`. + It guarantees each pair is unique and the coin types it records are sorted. ## Core functions 1. create_pool<A, B> + Create a new `Pool<A, B>` with initial liquidity. + Input with `Factory`, `Balance<A>` and `Balance<B>`, return `Balance<LP<A, B>>`. 2. create_pool_with_coins<A, B> + Input with `Factory`, `Coin<A>` and `Coin<B>`, return `Coin<LP<A, B>>`. 3. create_pool_with_coins_and_transfer_lp_to_sender<A, B> + Input with `Factory`, `Coin<A>` and `Coin<B>`, and transfer `Coin<LP<A, B>>` to sender in the function. 4. add_liquidity<A, B> + Add liquidity to `Pool<A, B>` to get LP coin. + Input with `Pool<A, B>`, `Balance<A>`, `Balance<B>` and minimal LP output amount, return remaining `Balance<A>`, `Balance<B>`, and `Balance<LP<A, B>>`. 5. add_liquidity_with_coins<A, B> + Input with `Pool<A, B>`, `Coin<A>`, `Coin<B>` and minimal LP output amount, return remaining `Coin<A>`, `Coin<B>`, and `Coin<LP<A, B>>`. 6. add_liquidity_with_coins_and_transfer_to_sender<A, B> + Input with `Pool<A, B>`, `Coin<A>`, `Coin<B>` and minimal LP output amount, and transfer remaining `Coin<A>`, `Coin<B>`, and `Coin<LP<A, B>>` to sender in the function. 7. remove_liquidity<A, B> + Remove liquidity from `Pool<A, B>` and burn LP coin. + Input with `Pool<A, B>`, `Balance<LP<A, B>>` and minimal A output amount, minimal B output amount, return `Balance<A>` and `Balance<B>`. 8. remove_liquidity_with_coins<A, B> + Input with `Pool<A, B>`, `Coin<LP<A, B>>` and minimal A output amount, minimal B output amount, return `Coin<A>` and `Coin<B>`. 9. remove_liquidity_with_coins_and_transfer_to_sender<A, B> + Input with `Pool<A, B>`, `Coin<LP<A, B>>` and minimal A output amount, minimal B output amount, and transfer `Coin<A>` and `Coin<B>` to sender in the function. 10. swap_a_for_b<A, B> + Swap exact `Balance<A>` for `Balance<B>`. + Input with `Pool<A, B>`, `Balance<A>` and minimal B output amount, return `Balance<B>`. 11. swap_a_for_b_with_coin<A, B> + Input with `Pool<A, B>`, `Coin<A>` and minimal B output amount, return `Coin<B>`. 12. swap_a_for_b_with_coin_and_transfer_to_sender<A, B> + Input with `Pool<A, B>`, `Coin<A>` and minimal B output amount, and transfer `Coin<B>` to sender in the function. 13. swap_b_for_a<A, B> + Swap exact `Balance<B>` for `Balance<A>`. + Input with `Pool<A, B>`, `Balance<B>` and minimal A output amount, return `Balance<A>`. 14. swap_b_for_a_with_coin<A, B> + Input with `Pool<A, B>`, `Coin<B>` and minimal A output amount, return `Coin<A>`. 15. swap_b_for_a_with_coin_and_transfer_to_sender<A, B> + Input with `Pool<A, B>`, `Coin<B>` and minimal A output amount, and transfer `Coin<A>` to sender in the function. ## Unit test