Re:Kotlin Money
by owlstuffing on Tuesday October 08, 2024 @05:32PM
(#41782033)
What you want is Money, currency is a _unit_ type of a Money quantity, just as meter is a unit type of Length.
Money cost = 25M USD;
cost += 12M EUR;
display(cost.to(EUR));
I don't think this makes sense? You need to specify an exchange rate somewhere.
> just as meter is a unit type of Length
The difference is that length units are fixed, but exchange rates are constantly changing.
Re:Kotlin Money
by owlstuffing on Wednesday October 09, 2024 @01:55AM
(#41784918)
> You need to specify an exchange rate somewhere.
Right. As I mentioned earlier exchange rate services would need to be integrated into the API.
Also, exchange rate services would not be needed until a conversion is necessary. For instance, when adding money of different currencies internally the Money type maintains currencies separately, subtotals for USD, EUR, etc. are managed. If at a later time the sum of Money should be displayed, deposited, etc. as a single currency, only then is an exchange service involved.
USD rent = 2000
EUR salary = 6000.53
USD disposableIncome = salary - rent
Then:
disposableIncome.toDecimal()
disposableIncome.toInteger()
disposableIncome.toString()
USD interest = disposableIncome.compoundInterest(startDate, endDate, apy)
USD tip = billTotal.tip(percentage)
USD and EUR would inherit from Money
Not sure how to implement it, might be a JVM magic thing.