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|
{-|
Ministries can be encoded to and decoded from JSON:
>>> import Data.Aeson (decode, encode)
>>> import Data.ByteString.Lazy.Char8 (pack)
>>> encode Defense
"\"Defense\""
>>> encode [ Defense, Welfare ]
"[\"Defense\",\"Welfare\"]"
>>> decode . pack $ "[ \"Science\" ]" :: Maybe [Ministry]
Just [Science]
-}
{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE DeriveGeneric #-}
module Malodivo.Types.Ministry
( Ministry(..)
, MinistryInfo
, MinistryLimits
, mi2ml
) where
import Control.Arrow ((&&&))
import GHC.Generics (Generic)
import Data.Aeson (FromJSON, ToJSON)
import qualified Data.HashMap.Strict as HM
import Data.Hashable (Hashable)
-- | Ministry of the Kingdom of Malodivo.
data Ministry
= Defense
| Science
| Welfare
deriving (Eq, Hashable, Show, Generic, FromJSON, ToJSON)
-- | Convenient type. Describes maximum money a ministry can get.
type MinistryLimits = HM.HashMap Ministry Integer
{-|
We use this data type instead of 'MinistryLimits' for JSON,
because maps other than @HashMap Text _@ are hard to decode/encode see
<https://github.com/bos/aeson/issues/79>. Anyway, we still have type-checked
typos-proof structure.
-}
data MinistryInfo = MinistryInfo
{ name :: Ministry
, amount :: Integer
} deriving (Generic, FromJSON)
mi2ml :: [MinistryInfo] -> MinistryLimits
mi2ml = HM.fromListWith (+) . map (name &&& amount)
|
