core / currency

# currency

`fun currency(code: String): Currency`

Defines a simple domain specific language for the specificiation of financial contracts. Currently covers:

- Some utilities for working with commands.

- Code for working with currencies.

- An Amount type that represents a positive quantity of a specific currency.

- A simple language extension for specifying requirements in English, along with logic to enforce them.

TODO: Look into replacing Currency and Amount with CurrencyUnit and MonetaryAmount from the javax.money API (JSR 354)