This package mainly provides 2 data types to represent and manipulate currencies according to the ISO 4217 standard.
It also provides a handful of instances for common typeclasses (Show, Read, Random, ToJSON, FromJSON, Val, Data, Typeable, Generic, NFData).
import Data.Aeson (ToJSON(..))
import Data.Currency (Currency, Alpha(..))
import GHC.Generics (Generic)
import qualified Safe
import qualified Data.Aeson as Aeson
import qualified Data.Currency as Currency
myCurrencies :: [Currency]
myCurrencies =
[ Currency.fromAlpha EUR
, Currency.fromAlpha USD
]
data Transaction = Transaction
{ amount :: Integer
, currency :: Currency
} deriving (Eq, Show, Generic)
instance ToJSON Transaction where
toJSON =
Aeson.genericToJSON Aeson.defaultOptions