Dex
The contract is responsible for launching new exchange pairs and serves as the automatic market maker engine. The contract manages pools for FA1.2/FA1.2, FA2/FA2 and FA2/FA1.2 tokens. The only instance of the pool for the same pair exists.
The contract fully implements the entrypoints of the FA2 standard according to TZIP-12. The other exchange-specific entrypoints are described in the doc.
types.ligo
type fa2_token_type is
record [
token_address : address;
token_id : nat;
]
type token_type is
| Fa12 of address
| Fa2 of fa2_token_type
type tokens_type is
[@layout:comb]
record [
token_a_type : token_type; (* token A standard *)
token_b_type : token_type; (* token B standard *)
]
type add_pair_params is
[@layout:comb]
record [
pair : tokens_type; (* exchange pair info *)
token_a_in : nat; (* min amount of tokens A invested *)
token_b_in : nat; (* min amount of tokens B invested *)
]
Setup the new exchange or relaunch the exchange after all the liquidity was drained.
amount_a_in and amount_b_in of tokens must be approved. Initial liquidity should be non-zero. All the storage parameters are reset to default values. The sender receives shares equal to a minimum of amount_a_in and amount_b_in. Tokens types must be provided in ascending order.Parameter | Type | Description |
|---|---|---|
token_a_type | tokens_type | The type of the first token |
token_b_type | tokens_type | The type of the second token |
token_a_in | nat | Amount of the first token to be invested |
token_b_in | nat | Amount of the second token to be invested |
type swap_type is
| A_to_b
| B_to_a
type swap_slice_type is
record [
pair_id : nat;
operation : swap_type;
]
type swap_type is
[@layout:comb]
record [
swaps : list(swap_slice_type);
amount_in : nat;
min_amount_out : nat;
receiver : address;
deadline : timestamp;
]
Swaps the token to another token.
a_to_b type is used to exchange token_a to token_b. b_to_a performs the opposite swap from token_b_address to token_a_address. The token_a and token_b are the corresponding tokens of pair_id pool. The amount_in of the token will be charged from the user. If the received amount is smaller than min_amount_out then the transaction is reverted. Tokens types must be provided in ascending order. Deadlines should be in the future.Parameter | Type | Description |
|---|---|---|
swaps | list of swap_slice_type | Swaps to perform; each swap consist of pair_id of the pool and swap_type to be executed; all the exchanges should be sequential. |
amount_in | nat | Amount of the token to swap |
min_amount_out | nat | The minimal amount of the token to receive |
receiver | address | Receiver's address |
deadline | timestamp | Time until the operation is valid |
type invest_type is
[@layout:comb]
record [
pair_id : nat;
shares : nat;
token_a_in : nat;
token_b_in : nat;
deadline : timestamp;
]
Adds more liquidity to the exchange.
token_a_in and token_b_in must be approved. Initial liquidity should be non-zero. The sender spends token_a_in and token_b_in at most otherwise, the transaction fails. Tokens types must be provided in ascending order. Deadlines should be in the future.Parameter | Type | Description |
|---|---|---|
pair_id | nat | Pair identifier |
shares | nat | Amount of LP tokens to mint |
token_a_in | nat | Max amount of the first token to invest |
token_b_in | nat | Max amount of the second token to invest |
deadline | timestamp | Time until the operation is valid |
type divest_type is
[@layout:comb]
record [
pair_id : nat;
min_token_a_out : nat;
min_token_b_out : nat;
shares : nat;
deadline : timestamp;
]
Burns
shares and sends tokens to the owner; operation is reverted if the amount of appropriate divested tokens is smaller than min_token_a_out or min_token_b_out. Tokens types must be provided in ascending order. Deadlines should be in the future.Parameter | Type | Description |
|---|---|---|
pair_id | nat | Pair identifier |
min_token_a_out | nat | Minimal amount of the first token to receive |
min_token_b_out | nat | Minimal amount of the second token to receive |
shares | nat | The amount of the shares to burn |
deadline | timestamp | Time until the operation is valid |
type close_type is unit
Is used after all the exchange calls to prevent reentrancy. It can only be called by the exchange itself.
type reserves_type is
record [
receiver : contract(nat * nat);
pair_id : nat;
]
Returns the amount of tokens reserves. No arguments are needed.
Last modified 8mo ago