> For the complete documentation index, see [llms.txt](https://wiki.zenlink.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wiki.zenlink.pro/zenlink-dex-protocol/interface.md). # Interface ## Module Assets Assets is the fundamental module of ZenLink Dex Protocol. Assets looks like ERC20. Users can manage liquidity and token with it. ### **Issue** Issue a new ERC20 token ``` fn issue(origin, #[compact] total: T::TokenBalance, asset_info: AssetInfo) ``` Parameters: * \`total\`: initial total supply. * \`asset\_info\`: the asset info contains \`name\`, \`symbol\`, \`decimals\`. ### **Transfer** Transfer token from owner to receiver. ``` fn transfer(origin, #[compact] id: T::AssetId, receiver: ::Source, #[compact] amount: T::TokenBalance) ``` Parameters: * \`target\`: the receiver of the asset. * \`amount\`: the amount of the asset to transfer. ### **Approve** Set `amount` as the allowance of `spender` over the caller’s tokens with token `id`. Returns a boolean value indicating whether the operation succeeded. ``` fn approve(origin, #[compact] id: T::AssetId, spender: ::Source, #[compact] amount: T::TokenBalance) ``` Parameters: * \`spender\`: the spender account. * \`amount\`: the amount of allowance. ### **Transfer From** Moves amount tokens from sender to recipient using the allowance mechanism. the amount is then deducted from the caller’s allowance. Returns a boolean value indicating whether the operation succeeded. ``` fn transfer_from(origin, #[compact] id: T::AssetId, from: ::Source, target: ::Source, # [compact] amount: T::TokenBalance) ``` Parameters: * \`id\`: the asset id. * \`from\`: the source of the asset to be transferred. * \`target\`: the receiver of the asset to be transferred. * \`amount\`: the amount of asset to be transferred. ## Module DEX Dex is the core module of ZenLink Dex Protocol. It implements the following functions: * Initializing token trading pair. * Token swap. * Adding/extracting liquidity. * Defining the liquidity constant function used throughout the protocol. ### **Create Pair** initializing trading pair. ``` pub fn create_pair( origin, token_0: AssetId, token_1: AssetId, )-> DispatchResult ``` Parameters: * origin: Trading account * token\_0: asset ID * token\_1: asset ID Description: * Token\_0 and Token\_1 represent the two assets that make up the trading pair (also known as the liquidity pool). * (token\_0, token\_1) and (token\_1, token\_0) is the same trading pair. ### **Add Liquidity** ``` pub fn add_liquidity( origin, token_0: AssetId, token_1: AssetId, amount_0_desired : T::TokenBalance, amount_1_desired : T::TokenBalance, amount_0_min : T::TokenBalance, amount_1_min : T::TokenBalance, target_parachain: ParaId, deadline: T::BlockNumber, )->DispatchResult ``` Parameters: * origin: Trading account * token\_0: The asset ID that makes up the trading pair * token\_1: The asset ID that makes up the trading pair * amount\_0\_desired: The token\_0 amount you want to deposit to the liquidity pool. * amount\_1\_desired: The token\_1 amount you want to deposit to the liquidity pool. * amount\_0\_min: The minimum token\_0 amount you expect to deposit to the liquidity pool. * amount\_1\_min: The minimum token\_1 amount you expect to deposit to the liquidity pool. * target\_parachain: The parachain ID of the liquidity pool. * deadline: The block deadline of this transaction. Description: Suppose in the following scenario: * Alice has ABC(the native asset of Parachain200) and XYZ(the native asset of Parachain300). * Alice wants to deposit liquidity to the ABC/XYZ liquidity pool. * ABC is represented on Parachain300 as ABC'. * The liquidity pool (trade pair ABC'/XYZ) is located on Parachain300. Exception: * If an add-liquidity transaction is made on Parachain200, please ensure enough Parachain300 assets(XYZ). Otherwise, the transaction must fail, and the Parachain200 assets(ABC) exist on Parachain300 in the form of ABC'. * If an add-liquidity transaction is made on Parachain300, please ensure enough Parachain200 assets on Parachain300(ABC'). If you don't have ABC', even if you have enough ABC on Parachain200, it will be a failed transaction. ### **Remove Liquidity** ``` pub fn remove_liquidity( origin, token_0: AssetId, token_1: AssetId, liquidity: T::TokenBalance, amount_token_0_min : T::TokenBalance, amount_token_1_min : T::TokenBalance, to: ::Source, deadline: T::BlockNumber, )->DispatchResult ``` Parameters: * origin: Trading account. * token\_0: The asset ID that makes up the trading pair. * token\_1: The asset ID that makes up the trading pair. * liquidity: The amount of liquidity you can hold up. * amount\_token\_0\_min: The minimum token\_0 amount you expect to be obtained after liquidity extraction. * amount\_token\_0\_min: The minimum token\_1 amount you expect to be obtained after liquidity extraction. * to: The recipient account. * deadline: The block deadline of this transaction. ### **Swap token\_0 with the exact amount for token\_1** ``` pub fn swap_exact_tokens_for_tokens( origin, amount_in: T::TokenBalance, amount_out_min: T::TokenBalance, path: Vec, to: ::Source, target_parachain: ParaId, deadline: T::BlockNumber, )->DispatchResult ``` Parameters: * origin: Trading account. * amount\_in: The exact token\_0 amount you want to send. * amount\_out\_min: The minimum token\_1 amount you expect to get. * path: The transaction path. * to: Recipient address. * target\_parachain: The parachain id of the liquidity pool. * deadline: The block deadline of this transaction. Description: * The path is represented as an array of asset ids. * The first element represents the asset being sent, and the last element represents the target asset. * \[A, B]: Exchange A for B in the A/B liquidity pool. * \[B, A]: Exchange B for A in the A/B liquidity pool. * \[A, B, C]: Exchange A for B in the A/B liquidity pool, then exchange B for C in the B/C liquidity pool. Additionally, * There is no limit to the length of the path. * The path is obtained from the API server. Since we currently have only one pool, the path length is fixed at 2. ### **Swap token\_0 for token\_1 with the exact amount** ``` pub fn swap_tokens_for_exact_tokens( origin, amount_out: T::TokenBalance, amount_in_max: T::TokenBalance, path: Vec, to: ::Source, deadline: T::BlockNumber, target_parachain: ParaId, )->DispatchResult ``` Parameters: * origin: Trading account. * amount\_out: The exact token\_1 amount you want to get. * amount\_in\_min: The minimum token\_0 amount you expect to send. * path: The transaction path. * to: Recipient address. * target\_parachain: The parachain id of the liquidity pool. * deadline: The block deadline of this transaction. Description: * The path is represented as an array of asset ids. * The first element represents the asset being sent, and the last element represents the target asset. * \[A, B]: Exchange A for B in the A/B liquidity pool. * \[B, A]: Exchange B for A in the A/B liquidity pool. * \[A, B, C]: Exchange A for B in the A/B liquidity pool, then exchange B for C in the B/C liquidity pool. Additionally, * There is no limit to the length of the path. * The path is obtained from the API server. Since we currently have only one pool, the path length is fixed at 2. ### **Transfer mapped/native assets in a parachain** ``` pub fn transfer( origin, asset_id: AssetId, target: ::Source, amount: T::TokenBalance )->DispatchResult ``` Parameters: * origin: Trading account * asset\_id: Asset id * target: Recipient address * amount: Asset amount Description: * This interface can only transfer assets that are mapped by other parachains to an account in a chain * such as transfer ABC' on Parachain300 to an account on Parachain300, rather than an account on Parach200. ### **Transfer mapped/native assets to another parachain** ``` pub fn transfer_to_parachain( origin, asset_id: AssetId, para_id: ParaId, account: T::AccountId, amount: T::TokenBalance ) -> DispatchResult ``` Parameters: * origin: Trading account * asset\_id: Asset id * para\_id: Target chain id * account: Recipient address * amount: Asset amount Description: * This interface can transfer mapped/native assets to an account in another parachain. * such as transfer ABC' or XYZ on Parachain300 to an account on Parachain200