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Merged
merged 7 commits into from
Apr 16, 2020
Merged

Add 'compose' for maps #672

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02f3997
Add 'compose' for maps
alexfmpe Jul 21, 2019
a7534a9
Fix typos
alexfmpe Oct 14, 2019
db55ad4
Cleanup
alexfmpe Oct 14, 2019
0c5c1e1
Force second argument of 'compose'
alexfmpe Dec 22, 2019
2bf99eb
Fix bounds
alexfmpe Dec 22, 2019
4a86a91
Merge branch 'master' into compose-maps
alexfmpe Dec 22, 2019
612020b
Merge branch 'master' into compose-maps
alexfmpe Apr 16, 2020
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5 changes: 5 additions & 0 deletions containers-tests/tests/intmap-properties.hs
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Expand Up @@ -13,6 +13,7 @@ import Data.IntMap.Internal.Debug (showTree)
import IntMapValidity (valid)

import Control.Applicative (Applicative(..))
import Control.Monad ((<=<))
import Data.Monoid
import Data.Maybe hiding (mapMaybe)
import qualified Data.Maybe as Maybe (mapMaybe)
Expand Down Expand Up @@ -174,6 +175,7 @@ main = defaultMain
, testProperty "lookupLE" prop_lookupLE
, testProperty "lookupGE" prop_lookupGE
, testProperty "disjoint" prop_disjoint
, testProperty "compose" prop_compose
, testProperty "lookupMin" prop_lookupMin
, testProperty "lookupMax" prop_lookupMax
, testProperty "findMin" prop_findMin
Expand Down Expand Up @@ -1243,6 +1245,9 @@ prop_intersectionWithKeyModel xs ys
prop_disjoint :: UMap -> UMap -> Property
prop_disjoint m1 m2 = disjoint m1 m2 === null (intersection m1 m2)

prop_compose :: IMap -> IMap -> Int -> Property
prop_compose bc ab k = (compose bc ab !? k) === ((bc !?) <=< (ab !?)) k

-- TODO: the second argument should be simply an 'IntSet', but that
-- runs afoul of our orphan instance.
prop_restrictKeys :: IMap -> IMap -> Property
Expand Down
6 changes: 5 additions & 1 deletion containers-tests/tests/map-properties.hs
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Expand Up @@ -13,7 +13,7 @@ import Data.Map.Internal.Debug (showTree, showTreeWith, balanced)
import Control.Applicative (Const(Const, getConst), pure, (<$>), (<*>))
import Control.Monad.Trans.State.Strict
import Control.Monad.Trans.Class
import Control.Monad (liftM4)
import Control.Monad (liftM4, (<=<))
import Data.Functor.Identity (Identity(Identity, runIdentity))
import Data.Monoid
import Data.Maybe hiding (mapMaybe)
Expand Down Expand Up @@ -180,6 +180,7 @@ main = defaultMain
, testProperty "intersectionWithKey" prop_intersectionWithKey
, testProperty "intersectionWithKeyModel" prop_intersectionWithKeyModel
, testProperty "disjoint" prop_disjoint
, testProperty "compose" prop_compose
, testProperty "differenceMerge" prop_differenceMerge
, testProperty "unionWithKeyMerge" prop_unionWithKeyMerge
, testProperty "mergeWithKey model" prop_mergeWithKeyModel
Expand Down Expand Up @@ -1160,6 +1161,9 @@ prop_intersectionWithKeyModel xs ys
prop_disjoint :: UMap -> UMap -> Property
prop_disjoint m1 m2 = disjoint m1 m2 === null (intersection m1 m2)

prop_compose :: IMap -> IMap -> Int -> Property
prop_compose bc ab k = (compose bc ab !? k) === ((bc !?) <=< (ab !?)) k

prop_mergeWithKeyModel :: [(Int,Int)] -> [(Int,Int)] -> Bool
prop_mergeWithKeyModel xs ys
= and [ testMergeWithKey f keep_x keep_y
Expand Down
22 changes: 22 additions & 0 deletions containers/src/Data/IntMap/Internal.hs
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Expand Up @@ -131,6 +131,9 @@ module Data.IntMap.Internal (
, intersectionWith
, intersectionWithKey

-- ** Compose
, compose

-- ** General combining function
, SimpleWhenMissing
, SimpleWhenMatched
Expand Down Expand Up @@ -765,6 +768,25 @@ disjoint t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
| zero p1 m2 = disjoint t1 l2
| otherwise = disjoint t1 r2

{--------------------------------------------------------------------
Compose
--------------------------------------------------------------------}
-- | /O(|ab|*min(|bc|,W))/. Relate the keys of one map to the values of
-- the other, by using the values of the former as keys for lookups
-- in the latter.
--
-- > compose (fromList [('a', "A"), ('b', "B")]) (fromList [(1,'a'),(2,'b'),(3,'z')]) = fromList [(1,"A"),(2,"B")]
--
-- @
-- ('compose' bc ab '!?') = (bc '!?') <=< (ab '!?')
-- @
--
-- @since UNRELEASED
compose :: IntMap c -> IntMap Int -> IntMap c
compose bc !ab
| null bc = empty
| otherwise = mapMaybe (bc !?) ab

{--------------------------------------------------------------------
Construction
--------------------------------------------------------------------}
Expand Down
3 changes: 3 additions & 0 deletions containers/src/Data/IntMap/Lazy.hs
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Expand Up @@ -146,6 +146,9 @@ module Data.IntMap.Lazy (
-- ** Disjoint
, disjoint

-- ** Compose
, compose

-- ** Universal combining function
, mergeWithKey

Expand Down
3 changes: 3 additions & 0 deletions containers/src/Data/IntMap/Strict.hs
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Expand Up @@ -165,6 +165,9 @@ module Data.IntMap.Strict (
-- ** Disjoint
, disjoint

-- ** Compose
, compose

-- ** Universal combining function
, mergeWithKey

Expand Down
22 changes: 22 additions & 0 deletions containers/src/Data/IntMap/Strict/Internal.hs
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Expand Up @@ -163,6 +163,9 @@ module Data.IntMap.Strict.Internal (
-- ** Disjoint
, disjoint

-- ** Compose
, compose

-- ** Universal combining function
, mergeWithKey

Expand Down Expand Up @@ -715,6 +718,25 @@ intersectionWithKey :: (Key -> a -> b -> c) -> IntMap a -> IntMap b -> IntMap c
intersectionWithKey f m1 m2
= mergeWithKey' bin (\(Tip k1 x1) (Tip _k2 x2) -> Tip k1 $! f k1 x1 x2) (const Nil) (const Nil) m1 m2

{--------------------------------------------------------------------
Compose
--------------------------------------------------------------------}
-- | /O(|ab|*min(|bc|,W))/. Relate the keys of one map to the values of
-- the other, by using the values of the former as keys for lookups
-- in the latter.
--
-- > compose (fromList [('a', "A"), ('b', "B")]) (fromList [(1,'a'),(2,'b'),(3,'z')]) = fromList [(1,"A"),(2,"B")]
--
-- @
-- ('compose' bc ab '!?') = (bc '!?') <=< (ab '!?')
-- @
--
-- @since UNRELEASED
compose :: IntMap c -> IntMap Int -> IntMap c
compose bc !ab
| null bc = empty
| otherwise = mapMaybe (bc !?) ab

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Same correction and comments apply here.

{--------------------------------------------------------------------
MergeWithKey
--------------------------------------------------------------------}
Expand Down
22 changes: 22 additions & 0 deletions containers/src/Data/Map/Internal.hs
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Expand Up @@ -192,6 +192,9 @@ module Data.Map.Internal (
-- ** Disjoint
, disjoint

-- ** Compose
, compose

-- ** General combining function
, SimpleWhenMissing
, SimpleWhenMatched
Expand Down Expand Up @@ -2088,6 +2091,25 @@ disjoint (Bin _ k _ l r) t
where
(lt,found,gt) = splitMember k t

{--------------------------------------------------------------------
Compose
--------------------------------------------------------------------}
-- | /O(|ab|*log(|bc|))/. Relate the keys of one map to the values of
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This bound is a bit funny when |bc| ≤ 1. Is it worth fixing? Not sure.

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Wouldn't that also apply to the existing O(n log n) bounds?
Big O notation is asymptotic, so in a sense there's nothing to fix.
Is there something specific about this bound you intend to make clearer? e.g. the if null bc case

-- the other, by using the values of the former as keys for lookups
-- in the latter.
--
-- > compose (fromList [('a', "A"), ('b', "B")]) (fromList [(1,'a'),(2,'b'),(3,'z')]) = fromList [(1,"A"),(2,"B")]
--
-- @
-- ('compose' bc ab '!?') = (bc '!?') <=< (ab '!?')
-- @
--
-- @since UNRELEASED
compose :: Ord b => Map b c -> Map a b -> Map a c
compose bc !ab
| null bc = empty
| otherwise = mapMaybe (bc !?) ab

#if !MIN_VERSION_base (4,8,0)
-- | The identity type.
newtype Identity a = Identity { runIdentity :: a }
Expand Down
3 changes: 3 additions & 0 deletions containers/src/Data/Map/Lazy.hs
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Expand Up @@ -166,6 +166,9 @@ module Data.Map.Lazy (
-- ** Disjoint
, disjoint

-- ** Compose
, compose

-- ** General combining functions
-- | See "Data.Map.Merge.Lazy"

Expand Down
3 changes: 3 additions & 0 deletions containers/src/Data/Map/Strict.hs
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Expand Up @@ -182,6 +182,9 @@ module Data.Map.Strict
-- ** Disjoint
, disjoint

-- ** Compose
, compose

-- ** General combining functions
-- | See "Data.Map.Merge.Strict"

Expand Down
22 changes: 22 additions & 0 deletions containers/src/Data/Map/Strict/Internal.hs
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Expand Up @@ -145,6 +145,9 @@ module Data.Map.Strict.Internal
-- ** Disjoint
, disjoint

-- ** Compose
, compose

-- ** General combining function
, SimpleWhenMissing
, SimpleWhenMatched
Expand Down Expand Up @@ -1200,6 +1203,25 @@ forceMaybe Nothing = Nothing
forceMaybe m@(Just !_) = m
{-# INLINE forceMaybe #-}

{--------------------------------------------------------------------
Compose
--------------------------------------------------------------------}
-- | /O(|ab|*log(|bc|))/. Relate the keys of one map to the values of
-- the other, by using the values of the former as keys for lookups
-- in the latter.
--
-- > compose (fromList [('a', "A"), ('b', "B")]) (fromList [(1,'a'),(2,'b'),(3,'z')]) = fromList [(1,"A"),(2,"B")]
--
-- @
-- ('compose' bc ab '!?') = (bc '!?') <=< (ab '!?')
-- @
--
-- @since UNRELEASED
compose :: Ord b => Map b c -> Map a b -> Map a c
compose bc !ab
| null bc = empty
| otherwise = mapMaybe (bc !?) ab

{--------------------------------------------------------------------
MergeWithKey
--------------------------------------------------------------------}
Expand Down