A simple currencies DSL implemented in Kotlin. It provides operations and exchange between currencies. By default it fetches exchange rates using the European Central Bank API https://exchangeratesapi.io but the user may add any other source

Gradle

implementation 'com.euapps:com.euapps.kcurrencies:0.0.2'

Maven

<dependency>
  <groupId>com.euapps</groupId>
  <artifactId>com.euapps.kcurrencies</artifactId>
  <version>0.0.2</version>
  <type>pom</type>
</dependency>

At this point the following 33 currencies are supported as defined by their ISO 4217 code:

EUR, CAD, HKD, ISK, PHP, DKK, HUF, CZK, AUD, RON, SEK, IDR, INR, BRL, RUB, HRK, JPY, THB, CHF, SGD, PLN, BGN, TRY, CNY, NOK, NZD, ZAR, USD, MXN, ILS, GBP, KRW, MYR

You may define a Currency instance using any number followed by a dot(.) and the ISO 4217 currency code

100.EUR
988.21.USD
1_238.91.CHF

You can convert between two currencies by using the to keyword followed by the ISO 4217 currency code

100.EUR to MXN
988.21.USD to EUR
1_238.91.CHF to USD

Note that any conversion is a suspend function since it performs an API call and should be run in a proper coroutine scope.

suspend fun main() {
    val billEur = 82.30.EUR
    println(billEur) // 82.30 EUR
    val billUsd = billEur to USD
    println(billUsd) // 91.15 USD
    val splitBill = billUsd / 3
    println(splitBill) // 30.38 USD
}

You may perform addition, subtraction multiplication and division of currencies using numeric operators.

100.EUR + 10.EUR
1000.EUR - 10.EUR
100.USD * 10
1000.CHF / 2

Operations between two different currencies convert the second operand to the currency of the first and perform the operation.

1000.EUR + 500.USD
1000.USD - 10.EUR

By default the number of digits to the right of the decimal point (scale) is two(2). This may change statically like bellow:

Currency.scale = 3

By default the rounding mode is Round half to even (known as bankers' rounding). This can be changed like bellow

Currency.roundingMode = RoundingMode.DOWN

By default the currency rates are fetched from the European Central Bank API https://exchangeratesapi.io. The user may change this by providing a custom function. For example the code bellow returns a rate 2 for any provided currencies:

Currency.exchange = { base: CurrencyCode, currency: CurrencyCode -> BigDecimal(2.0) }