{-# OPTIONS -cpp -fglasgow-exts -fno-bang-patterns #-}
-----------------------------------------------------------------------------
+-- |
-- Module : Data.IntMap
-- Copyright : (c) Daan Leijen 2002
-- License : BSD-style
--
-- An efficient implementation of maps from integer keys to values.
--
--- This module is intended to be imported @qualified@, to avoid name
--- clashes with "Prelude" functions. eg.
+-- Since many function names (but not the type name) clash with
+-- "Prelude" names, this module is usually imported @qualified@, e.g.
--
--- > import Data.IntMap as Map
+-- > import Data.IntMap (IntMap)
+-- > import qualified Data.IntMap as IntMap
--
-- The implementation is based on /big-endian patricia trees/. This data
-- structure performs especially well on binary operations like 'union'
, partition
, partitionWithKey
+ , mapMaybe
+ , mapMaybeWithKey
+ , mapEither
+ , mapEitherWithKey
+
, split
, splitLookup
| otherwise -> (Nil,t)
Nil -> (Nil,Nil)
+-- | /O(n)/. Map values and collect the 'Just' results.
+mapMaybe :: (a -> Maybe b) -> IntMap a -> IntMap b
+mapMaybe f m
+ = mapMaybeWithKey (\k x -> f x) m
+
+-- | /O(n)/. Map keys\/values and collect the 'Just' results.
+mapMaybeWithKey :: (Key -> a -> Maybe b) -> IntMap a -> IntMap b
+mapMaybeWithKey f (Bin p m l r)
+ = bin p m (mapMaybeWithKey f l) (mapMaybeWithKey f r)
+mapMaybeWithKey f (Tip k x) = case f k x of
+ Just y -> Tip k y
+ Nothing -> Nil
+mapMaybeWithKey f Nil = Nil
+
+-- | /O(n)/. Map values and separate the 'Left' and 'Right' results.
+mapEither :: (a -> Either b c) -> IntMap a -> (IntMap b, IntMap c)
+mapEither f m
+ = mapEitherWithKey (\k x -> f x) m
+
+-- | /O(n)/. Map keys\/values and separate the 'Left' and 'Right' results.
+mapEitherWithKey :: (Key -> a -> Either b c) -> IntMap a -> (IntMap b, IntMap c)
+mapEitherWithKey f (Bin p m l r)
+ = (bin p m l1 r1, bin p m l2 r2)
+ where
+ (l1,l2) = mapEitherWithKey f l
+ (r1,r2) = mapEitherWithKey f r
+mapEitherWithKey f (Tip k x) = case f k x of
+ Left y -> (Tip k y, Nil)
+ Right z -> (Nil, Tip k z)
+mapEitherWithKey f Nil = (Nil, Nil)
-- | /O(log n)/. The expression (@'split' k map@) is a pair @(map1,map2)@
-- where all keys in @map1@ are lower than @k@ and all keys in