Arithmetic that works on a type alias of json.Number, inspired by SQLite.

Since Number is a string, literals are valid numbers, and you can do:

decimal.Sum("0.1", "0.1", "0.1", "-0.3") // == "0"

All operations produce exact results, with arbitrary precision (which is why we can't have decimal.Div).

Instead, we have decimal.Split (and decimal.Allocate) to distribute an amount amongst parties without loosing units to rounding.

decimal.Split("0.99", "0.01", 2) // == ["0.5", "0.49"]
decimal.Allocate("100", "0.05", 2, 3, 2) // == ["28.6", "48.85", "28.55"]

We also have operations to round amounts to multiples of a unit under various rounding modes.

The library won't win any performance prizes, but you may find the API more ergonomic than alternatives.