A simple Sui Move version AMM Dex based on the logic of srmV1.

Introduction

• This module implements the factory and pool logic of srmV1 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 not sorted to allow for control over coinA. This is a requirement for how the dex functions to ensure rewards are delivered in the correct coinA.

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