Change values to use foldr for improved speed (#61)

Since this implementation does not traverse
through an intermediary list multiple times,
it is must faster

Author: JordanMartinez

CHANGELOG.md

@@ -10,7 +10,7 @@ Breaking changes:
 New features:
 - Exported `Data.Map.Internal` data constructors (#52 by @natefaubion)
 - Add unbiased `Semigroup`/`Monoid` instances to `Map` with `Warn` (#54 by @JordanMartinez)
-- Improved speed of `foldr`, `foldl`, `foldMap`, `foldlWithIndex`, `foldrWithIndex`, `foldMapWithIndex`, `unionWith` (#60 by @xgrommx)
+- Improved speed of `foldr`, `foldl`, `foldMap`, `foldlWithIndex`, `foldrWithIndex`, `foldMapWithIndex`, `unionWith`, and `values` (#60 by @xgrommx, #61 by @JordanMartinez)
 
 Bugfixes:
 

bench/Bench/Data/Map.purs

@@ -36,6 +36,12 @@ benchMap = do
   log "---------------"
   benchUnion
 
+  log ""
+
+  log "values"
+  log "---------------"
+  benchValues
+
   where
 
   benchUnion = do
@@ -56,6 +62,20 @@ benchMap = do
     log $ "M.union: big map (" <> show size' <> ")"
     benchWith 10 \_ -> M.union bigMap' bigMap2'
 
+  benchValues = do
+    let nats = L.range 0 999999
+        natPairs = (flip Tuple) unit <$> nats
+        bigMap = Map2a0bff.fromFoldable $ natPairs
+        bigMap' = M.fromFoldable $ natPairs
+        size = Map2a0bff.size bigMap
+        size' = M.size bigMap'
+
+    log $ "Map2a0bff.values: big map (" <> show size <> ")"
+    benchWith 10 \_ -> Map2a0bff.values bigMap
+
+    log $ "M.values: big map (" <> show size' <> ")"
+    benchWith 10 \_ -> M.values bigMap'
+
   benchSize = do
     let nats = L.range 0 999999
         natPairs = (flip Tuple) unit <$> nats

src/Data/Map/Internal.purs

@@ -657,9 +657,7 @@ keys (Three left k1 _ mid k2 _ right) = keys left <> pure k1 <> keys mid <> pure
 
 -- | Get a list of the values contained in a map
 values :: forall k v. Map k v -> List v
-values Leaf = Nil
-values (Two left _ v right) = values left <> pure v <> values right
-values (Three left _ v1 mid _ v2 right) = values left <> pure v1 <> values mid <> pure v2 <> values right
+values = foldr Cons Nil
 
 -- | Compute the union of two maps, using the specified function
 -- | to combine values for duplicate keys.