bb3d0dc · elk · git.iko.soy

1−module Dict (empty,singleton,insert

1+module Dict (empty,singleton,insert,update

2 ,lookup,findWithDefault

3 ,remove,member

4 ,foldl,foldr,map

14Insert, remove, and query operations all take *O(log n)* time.

15

16# Build

17−@docs empty, singleton, insert, remove

17+@docs empty, singleton, insert, update, remove

18

19# Query

20@docs member, lookup, findWithDefault

148{-| Insert a key-value pair into a dictionary. Replaces value when there is

149a collision. -}

150insert : comparable -> v -> Dict comparable v -> Dict comparable v

151+insert k v t = let updater _ = v

152+ in update k updater t

153+

154+{-| Update the value of a dictionary for a specific key with a given function. -}

155+update : comparable -> (Maybe v -> v) -> Dict comparable v -> Dict comparable v

151−insert k v t = -- Invariant: t is a valid left-leaning rb tree

156+update k u t = -- Invariant: t is a valid left-leaning rb tree

152− let ins t =

157+ let up t =

153 case t of

158 case t of

159+ -- Insert case

154− RBEmpty LBlack -> RBNode Red k v (RBEmpty LBlack) (RBEmpty LBlack)

160+ RBEmpty LBlack -> RBNode Red k (u Nothing) (RBEmpty LBlack) (RBEmpty LBlack)

155 RBNode c k' v' l r ->

161 RBNode c k' v' l r ->

156 let h = case Native.Utils.compare k k' of

162 let h = case Native.Utils.compare k k' of

157− LT -> RBNode c k' v' (ins l) r

163+ LT -> RBNode c k' v' (up l) r

158− EQ -> RBNode c k' v l r -- replace

164+ EQ -> RBNode c k' (u (Just v')) l r -- update case

159− GT -> RBNode c k' v' l (ins r)

165+ GT -> RBNode c k' v' l (up r)

160 in fixUp h

166 in fixUp h

161− in ensureBlackRoot (ins t)

167+ in ensureBlackRoot (up t)

162

168

163{-| Create a dictionary with one key-value pair. -}

169{-| Create a dictionary with one key-value pair. -}

164singleton : comparable -> v -> Dict comparable v

170singleton : comparable -> v -> Dict comparable v