Swap of Ada and dollar tokens

metadata.json

{"valueParameterDescriptions":[["Amount of Ada","Amount of Ada to be exchanged for dollars."],["Amount of dollars","Amount of dollar tokens to be exchanged for Ada."]],"slotParameterDescriptions":[["Timeout for Ada deposit","Deadline by which Ada must be deposited."],["Timeout for dollar deposit","Deadline by which dollar tokens must be deposited (must be after the deadline for Ada deposit)."]],"roleDescriptions":[["Ada provider","The party that provides the Ada."],["Dollar provider","The party that provides the dollar tokens."]],"contractType":"S","contractName":"Swap of Ada and dollar tokens","contractDescription":"Takes Ada from one party and dollar tokens from another party, and it swaps them atomically.","choiceDescriptions":[]}

playground.js

    /* We can set explicitRefunds true to run Close refund analysis
       but we get a shorter contract if we set it to false */
    const explicitRefunds: Boolean = false;

    const lovelacePerAda: Value = Constant(1000000n);
    const amountOfAda: Value = ConstantParam("Amount of Ada");
    const amountOfLovelace: Value = MulValue(lovelacePerAda, amountOfAda);
    const amountOfDollars: Value = ConstantParam("Amount of dollars");

    const adaDepositTimeout: Timeout = SlotParam("Timeout for Ada deposit");
    const dollarDepositTimeout: Timeout = SlotParam("Timeout for dollar deposit");

    const dollars: Token = Token("85bb65", "dollar")

    type SwapParty = {
        party: Party;
        currency: Token;
        amount: Value;
    };

    const adaProvider: SwapParty = {
        party: Role("Ada provider"),
        currency: ada,
        amount: amountOfLovelace
    }

    const dollarProvider: SwapParty = {
        party: Role("Dollar provider"),
        currency: dollars,
        amount: amountOfDollars
    }

    function makeDeposit(src: SwapParty, timeout: Timeout,
        timeoutContinuation: Contract, continuation: Contract): Contract {
        return When([Case(Deposit(src.party, src.party, src.currency, src.amount),
            continuation)],
            timeout,
            timeoutContinuation);
    }

    function refundSwapParty(party: SwapParty): Contract {
        if (explicitRefunds) {
            return Pay(party.party, Party(party.party), party.currency, party.amount, Close);
        } else {
            return Close;
        }
    }

    const makePayment = function (src: SwapParty, dest: SwapParty,
        continuation: Contract): Contract {
        return Pay(src.party, Party(dest.party), src.currency, src.amount,
            continuation);
    }

    const contract: Contract = makeDeposit(adaProvider, adaDepositTimeout, Close,
        makeDeposit(dollarProvider, dollarDepositTimeout, refundSwapParty(adaProvider),
            makePayment(adaProvider, dollarProvider,
                makePayment(dollarProvider, adaProvider,
                    Close))))

    return contract;

playground.marlowe.json

{}