launch_exchange

An entrypoint that launches a new exchanges. Next types of exchanges are supported:

• FA1.2/FA1.2;

• FA1.2/FA2;

• FA1.2/TEZ;

• FA2/FA1.2;

• FA2/FA2;

• FA2/TEZ;

• TEZ/FA1.2;

• TEZ/FA2.

In case of TOK/TEZ exchange launch voting in appropriative Bucket contract is executed. Also all TEZ tokens is transferred to the same Bucket contract before voting.

In time of first exchange launch, this contract calls launch_callback entrypoint. This is done in order to vote on a Bucket contract that has just been deployed and cannot be accessed until the launch exchange transaction completes. Therefore, voting takes place in the next transaction, sent from launch_callback.

Call parameters

type tez_t              is unit

type fa12_token_t       is address

type fa2_token_t        is [@layout:comb] record [
  token                   : address;
  id                      : nat;
]

type token_t            is
| Tez                     of tez_t
| Fa12                    of fa12_token_t
| Fa2                     of fa2_token_t

type tokens_t           is [@layout:comb] record [
  token_a                 : token_t;
  token_b                 : token_t;
]

type launch_exchange_t  is [@layout:comb] record [
  pair                    : tokens_t;
  token_a_in              : nat;
  token_b_in              : nat;
  shares_receiver         : address;
  candidate               : key_hash;
  deadline                : timestamp;
]

tokens_t

Field	Type	Description
token_a	token_t	FA1.2/FA2/TEZ token
token_b	token_t	FA1.2/FA2/TEZ token

launch_exchange_t

Field	Type	Description
pair	tokens_t	Tokens to launch exchange with
token_a_in	nat	Amount of token A for investment
token_b_in	nat	Amount of token B for investment
shares_receiver	address	Receiver of LP tokens
candidate	key_hash	Baker for voting (is used only in case of TOK/TEZ exchanges launch). Ignored otherwise
deadline	timestamp	The time until which the transaction remains valid and will not be rejected

Usage

Note: you need to pass positive TEZ/mutez amount to the send() method in case of FA1.2/TEZ or FA2/TEZ exchanges launch (see example below).

Also don't forget to add the DexCore contract as the operator for your FA2 tokens or make an approve for spending of FA1.2 tokens in time of exchange launch.

🌮 Taquito

const dexCoreAddress = "KT1...";
const params = {
    pair: {
        token_a: {
            fa12: "KT1...",
        }, 
        token_b: {
            tez: undefined,
        },
    },
    token_a_in: 100,
    token_b_in: 100,
    shares_receiver: "tz1.../KT1...",
    candidate: "tz1...",
    deadline: String(Date.parse((await tezos.rpc.getBlockHeader()).timestamp) / 1000 + 100),
};
const dexCore = await tezos.contract.at(dexCoreAddress);
const operation = await dexCore.methodsObject.launch_exchange(params).send({ amount: params.token_b_in, mutez: true });

await operation.confirmation();

Pass candidate: "tz1ZZZZZZZZZZZZZZZZZZZZZZZZZZZZNkiRg"in case of launching TOK/TOK exchange

Errors

• 104 - wrong order of a tokens from parameters.

• 105 - zero token A amount in.

• 106 - zero token B amount in.

• 107 - pair (pool) with the specified token_id already listed.

• 120 - wrong TEZ amount were passed to the transaction.

• 136 - reentrancy.

• 144 - action outdated (the time until which the transaction remained valid was passed).

• 412 - non payable entrypoint (can't accept TEZ tokens during call of an entrypoint). Only in case of launching of TOK/TOK liquidity pools (pairs).