mirror of
https://github.com/github/semantic.git
synced 2025-01-06 23:46:21 +03:00
54 lines
1.6 KiB
Haskell
54 lines
1.6 KiB
Haskell
module OrderedMap (
|
|
OrderedMap
|
|
, fromList
|
|
, toList
|
|
, keys
|
|
, (!)
|
|
, OrderedMap.lookup
|
|
, size
|
|
, empty
|
|
, union
|
|
, unions
|
|
, intersectionWith
|
|
, difference
|
|
) where
|
|
|
|
data OrderedMap key value = OrderedMap { toList :: [(key, value)] }
|
|
deriving (Show, Eq, Functor, Foldable, Traversable)
|
|
|
|
fromList :: [(key, value)] -> OrderedMap key value
|
|
fromList list = OrderedMap list
|
|
|
|
keys :: OrderedMap key value -> [key]
|
|
keys (OrderedMap pairs) = fst <$> pairs
|
|
|
|
infixl 9 !
|
|
|
|
(!) :: Eq key => OrderedMap key value -> key -> value
|
|
map ! key = case OrderedMap.lookup key map of
|
|
Just value -> value
|
|
Nothing -> error "no value found for key"
|
|
|
|
lookup :: Eq key => key -> OrderedMap key value -> Maybe value
|
|
lookup key = Prelude.lookup key . toList
|
|
|
|
size :: OrderedMap key value -> Int
|
|
size = length . toList
|
|
|
|
empty :: OrderedMap key value
|
|
empty = OrderedMap []
|
|
|
|
union :: Eq key => OrderedMap key value -> OrderedMap key value -> OrderedMap key value
|
|
union (OrderedMap a) (OrderedMap b) = OrderedMap $ a ++ filter (not . (`elem` extant) . fst) b
|
|
where extant = fst <$> a
|
|
|
|
unions :: Eq key => [OrderedMap key value] -> OrderedMap key value
|
|
unions = foldl union empty
|
|
|
|
intersectionWith :: Eq key => (a -> b -> c) -> OrderedMap key a -> OrderedMap key b -> OrderedMap key c
|
|
intersectionWith combine (OrderedMap a) (OrderedMap b) = OrderedMap $ a >>= (\ (key, value) -> maybe [] (pure . ((,) key) . combine value) $ Prelude.lookup key b)
|
|
|
|
difference :: Eq key => OrderedMap key a -> OrderedMap key b -> OrderedMap key a
|
|
difference (OrderedMap a) (OrderedMap b) = OrderedMap $ filter (not . (`elem` extant) . fst) a
|
|
where extant = fst <$> b
|