module Data.DefaultMap
where
import Data.Map (Map)
import qualified Data.Map as Map
data DefaultMap k v = DefMap { defDefault :: v
, defMap :: Map k v
} deriving (Read, Show, Eq, Ord)
empty :: v -> DefaultMap k v
empty def = DefMap { defDefault = def
, defMap = Map.empty }
lookup :: Ord k => k -> DefaultMap k v -> v
lookup k m = Map.findWithDefault (defDefault m) k (defMap m)
fromList :: Ord k => v -> [(k, v)] -> DefaultMap k v
fromList def entries = DefMap { defDefault = def
, defMap = Map.fromList entries }
keys :: DefaultMap k a -> [k]
keys m = Map.keys (defMap m)
foldl :: (a -> b -> a) -> a -> DefaultMap k b -> a
foldl fn acc m = Map.foldl fn acc (defMap m)