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2−{-# LANGUAGE ConstraintKinds #-}
3−{-# LANGUAGE FlexibleContexts #-}
4−{-# LANGUAGE FlexibleInstances #-}
6−{-# LANGUAGE InstanceSigs #-}
7−{-# LANGUAGE LambdaCase #-}
8−{-# LANGUAGE MultiParamTypeClasses #-}
9−{-# LANGUAGE PatternGuards #-}
10−{-# LANGUAGE PolyKinds #-}
11−{-# LANGUAGE Rank2Types #-}
12−{-# LANGUAGE ScopedTypeVariables #-}
13−{-# LANGUAGE StandaloneDeriving #-}
14−{-# LANGUAGE TypeFamilies #-}
15−{-# LANGUAGE UndecidableInstances #-}
16−{-# LANGUAGE UndecidableSuperClasses #-}
18−-- |Module containing @'PatchDMapWithPatchingMove' k v@ and associated functions, which represents a 'Patch' to a @'DMap' k v@ which can insert, update, delete, and
19−-- move values between keys.
20−module Data.Patch.DMapWithPatchingMove where
22−import qualified Control.Category as Cat
23−import qualified Control.Category.DecidablyEmpty as Cat
25−import Data.Constraint.Extras (Has')
26−import Data.Dependent.Map (DMap)
27−import Data.Dependent.Sum (DSum (..))
28−import qualified Data.Dependent.Map as DMap
29−import Data.Functor.Constant (Constant (..))
30−import Data.Functor.Misc
31− ( Const2 (..), Proxy3 (..)
35−import Data.Functor.Const (Const (..))
36−import Data.Functor.Product (Product (..))
37−import Data.GADT.Compare (GEq (..), GCompare (..))
38−import Data.GADT.Show (GRead, GShow, gshow)
39−import qualified Data.Map as Map
41−import Data.Monoid.DecidablyEmpty
42−import Data.Semigroupoid as Cat
43−#if !MIN_VERSION_base(4,11,0)
44−import Data.Semigroup (Semigroup (..), (<>))
46−import Data.Some (Some (Some), mkSome)
47−import Data.Proxy (Proxy (..))
48−import Data.These (These (..))
49−import Data.Type.Equality ((:~:)(..))
51−import Data.Patch.Class
52− ( Patch (..), PatchHet (..)
53− , PatchHet2 (..), PatchSource1, PatchTarget1
56−import Data.Patch.MapWithPatchingMove (PatchMapWithPatchingMove (..))
57−import qualified Data.Patch.MapWithPatchingMove as MapWithPatchingMove
59−-- | Like 'PatchMapWithPatchingMove', but for 'DMap'. Each key carries a 'NodeInfo'
60−-- which describes how it will be changed by the patch and connects move sources
65−-- * A key should not move to itself.
67−-- * A move should always be represented with both the destination key (as a
68−-- 'From_Move') and the source key (as a @'ComposeMaybe' ('Just'
70−newtype PatchDMapWithPatchingMove k v = PatchDMapWithPatchingMove (DMap k (NodeInfo k v))
72−--deriving instance ( GShow k
74−-- , Has' Show k (PatchTarget1 p)
75−-- ) => Show (PatchDMapWithPatchingMove k p)
76−--deriving instance ( GRead k
78−-- , Has' Read k (PatchTarget1 p)
79−-- ) => Read (PatchDMapWithPatchingMove k p)
80−--deriving instance ( GEq k
82−-- , Has' Eq k (PatchTarget1 p)
83−-- ) => Eq (PatchDMapWithPatchingMove k p)
84−--deriving instance ( GCompare k
86−-- , Has' Ord k (PatchTarget1 p)
87−-- ) => Ord (PatchDMapWithPatchingMove k p)
89−-- It won't let me derive for some reason
91− , Cat.DecidablyEmpty v
94− , PatchSource1 v ~ PatchTarget1 v
95− ) => DecidablyEmpty (PatchDMapWithPatchingMove k v) where
96− isEmpty (PatchDMapWithPatchingMove m) = DMap.null m
98−-- | Structure which represents what changes apply to a particular key.
99−-- @_nodeInfo_from@ specifies what happens to this key, and in particular what
100−-- other key the current key is moving from, while @_nodeInfo_to@ specifies what
101−-- key the current key is moving to if involved in a move.
102−data NodeInfo k p a = NodeInfo
103− { _nodeInfo_from :: !(From k p a)
104− -- ^ Change applying to the current key, be it an insert, move, or delete.
105− , _nodeInfo_to :: !(To k)
106− -- ^ Where this key is moving to, if involved in a move. Should only be
107− -- @ComposeMaybe (Just k)@ when there is a corresponding 'From_Move'.
110−--deriving instance ( Show (k a)
112−-- , Show (PatchTarget1 p a)
113−-- ) => Show (NodeInfo k p a)
114−--deriving instance ( Read (k a)
116−-- , Read (PatchTarget1 p a)
117−-- ) => Read (NodeInfo k p a)
118−--deriving instance ( Eq (k a)
120−-- , Eq (PatchTarget1 p a)
121−-- ) => Eq (NodeInfo k p a)
122−--deriving instance ( Ord (k a)
124−-- , Ord (PatchTarget1 p a)
125−-- ) => Ord (NodeInfo k p a)
127−-- | Structure describing a particular change to a key, be it inserting a new
128−-- key (@From_Insert@), updating an existing key (@From_Insert@ again), deleting
129−-- a key (@From_Delete@), or moving a key (@From_Move@).
131−-- This type isn't used directly as the from field patch, but is instead wrapped
132−-- in an existential. However, it is nice to be able to reason about this in
133−-- isolation as it is itself a @Semigroupoid@ when the underlying patch is.
134−data From (k :: a -> *) (p :: a -> a -> *) :: a -> * where
135− -- | Insert a new or update an existing key with the given value @PatchTarget1
137− From_Insert :: PatchTarget1 p to -> From k p to
138− -- | Delete the existing key
139− From_Delete :: From k p to
140− -- | Move the value from the given key @k a@ to this key. The source key
141− -- should also have an entry in the patch giving the current key as
142− -- @_nodeInfo_to@, usually but not necessarily with @From_Delete@.
143− From_Move :: !(DSum k (Flip p to)) -> From k p to
145−deriving instance ( Show (k a), GShow k
146− , Has' Show k (Flip p a)
147− , Show (PatchTarget1 p a)
148− ) => Show (From k p a)
149−deriving instance ( Read (k a), GRead k
150− , Has' Read k (Flip p a)
151− , Read (PatchTarget1 p a)
152− ) => Read (From k p a)
153−deriving instance ( GEq k
154− , Has' Eq k (Flip p a)
155− , Eq (PatchTarget1 p a)
156− ) => Eq (From k p a)
157−deriving instance ( GCompare k
158− , Has' Eq k (Flip p a) -- superclass bug
159− , Has' Ord k (Flip p a)
160− , Ord (PatchTarget1 p a)
161− ) => Ord (From k p a)
163−newtype Flip p to from = Flip (p from to)
165−instance Cat.Category p => Cat.Category (Flip (p :: k -> k -> *)) where
167− Flip y . Flip x = Flip $ x Cat.. y
169−-- | The "to" part of a 'NodeInfo'. Rather than be built out of @From@ like @From@
170−-- is, we store just the information necessary to compose a @To@ and @From@ like
171−-- @oLocal@ composes two @From@s.
172−data To (k :: a -> *) where
173− -- | Delete or leave in place
175− -- | Move the value from the given key @k a@ to this key. The target key
176− -- should also have an entry in the patch giving the current key in
177− -- @_nodeInfo_from@, usually but not necessarily with @To_Delete@.
178− To_Move :: !(Some k) -> To k
180−deriving instance GShow k => Show (To k)
181−deriving instance GRead k => Read (To k)
182−deriving instance GEq k => Eq (To k)
183−deriving instance GCompare k => Ord (To k)
185−-- |Test whether a 'PatchDMapWithPatchingMove' satisfies its invariants.
186−validPatchDMapWithPatchingMove
188− . (GCompare k, GShow k)
189− => DMap k (NodeInfo k v)
191−validPatchDMapWithPatchingMove = not . null . validationErrorsForPatchDMapWithPatchingMove
193−-- |Enumerate what reasons a 'PatchDMapWithPatchingMove' doesn't satisfy its invariants, returning @[]@ if it's valid.
194−validationErrorsForPatchDMapWithPatchingMove
196− . (GCompare k, GShow k)
197− => DMap k (NodeInfo k v)
199−validationErrorsForPatchDMapWithPatchingMove m =
200− noSelfMoves <> movesBalanced
202− noSelfMoves = mapMaybe selfMove . DMap.toAscList $ m
203− selfMove (dst :=> NodeInfo (From_Move (src :=> _)) _)
204− | Just _ <- dst `geq` src = Just $ "self move of key " <> gshow src <> " at destination side"
205− selfMove (src :=> NodeInfo _ (To_Move (Some dst)))
206− | Just _ <- src `geq` dst = Just $ "self move of key " <> gshow dst <> " at source side"
207− selfMove _ = Nothing
208− movesBalanced = mapMaybe unbalancedMove . DMap.toAscList $ m
209− unbalancedMove (dst :=> NodeInfo (From_Move (src :=> _)) _) =
210− case DMap.lookup src m of
211− Nothing -> Just $ "unbalanced move at destination key " <> gshow dst <> " supposedly from " <> gshow src <> " but source key is not in the patch"
212− Just (NodeInfo _ (To_Move (Some dst'))) ->
213− if isNothing (dst' `geq` dst)
214− then Just $ "unbalanced move at destination key " <> gshow dst <> " from " <> gshow src <> " is going to " <> gshow dst' <> " instead"
217− Just $ "unbalanced move at destination key " <> gshow dst <> " supposedly from " <> gshow src <> " but source key has no move to key"
218− unbalancedMove (src :=> NodeInfo _ (To_Move (Some dst))) =
219− case DMap.lookup dst m of
220− Nothing -> Just $ " unbalanced move at source key " <> gshow src <> " supposedly going to " <> gshow dst <> " but destination key is not in the patch"
221− Just (NodeInfo (From_Move (src' :=> _)) _) ->
222− if isNothing (src' `geq` src)
223− then Just $ "unbalanced move at source key " <> gshow src <> " to " <> gshow dst <> " is coming from " <> gshow src' <> " instead"
227− Just $ "unbalanced move at source key " <> gshow src <> " supposedly going to " <> gshow dst <> " but destination key is not moving"
228− unbalancedMove _ = Nothing
231−data ToFrom k p a = ToFrom (To k) (From k p a)
233−-- | Helper data structure used for composing patches using the monoid instance.
236− | Fixup_Update (These (DSum k (From k p)) (To k))
238−-- | Compose patches having the same effect as applying the patches in turn:
239−-- @'applyAlways' (p <> q) == 'applyAlways' p . 'applyAlways' q@
242− , Cat.Semigroupoid p
243− , Cat.DecidablyEmpty p
245− , PatchSource1 p ~ PatchTarget1 p
247− => Semigroup (PatchDMapWithPatchingMove k p) where
248− PatchDMapWithPatchingMove ma <> PatchDMapWithPatchingMove mb = PatchDMapWithPatchingMove m
250− connections :: [DSum k (ToFrom k p)]
251− connections = DMap.toList $ DMap.intersectionWithKey
252− (\_ a b -> ToFrom (_nodeInfo_to a) (_nodeInfo_from b))
255− h :: DSum k (ToFrom k p) -> [DSum k (Const (Fixup k p))]
256− h ((between :: k between) :=> ToFrom editAfter editBefore) = case (editAfter, editBefore) of
257− (To_Move (Some (toAfter :: k after)), From_Move ((fromBefore :: k before) :=> Flip p) :: From k p between) ->
260− [ toAfter :=> Const Fixup_Delete ]
262− [ toAfter :=> Const (Fixup_Update $ This $ between :=> editBefore)
263− , fromBefore :=> Const (Fixup_Update $ That editAfter)
265− (To_NonMove, From_Move (fromBefore :=> _)) ->
266− -- The item is destroyed in the second patch, so indicate that it is
267− -- destroyed in the source map
268− [fromBefore :=> Const (Fixup_Update $ That To_NonMove)]
269− (To_Move (Some toAfter), _) ->
270− [toAfter :=> Const (Fixup_Update $ This $ between :=> editBefore)]
273− mergeFixups _ (Const Fixup_Delete) (Const Fixup_Delete) = Const $ Fixup_Delete
274− mergeFixups _ (Const (Fixup_Update a)) (Const (Fixup_Update b))
275− | This x <- a, That y <- b
276− = Const $ Fixup_Update $ These x y
277− | That y <- a, This x <- b
278− = Const $ Fixup_Update $ These x y
279− mergeFixups _ _ _ = error "PatchDMapWithPatchingMove: incompatible fixups"
280− fixups = DMap.fromListWithKey mergeFixups $ concatMap h connections
281− combineNodeInfos _ nia nib = NodeInfo
282− { _nodeInfo_from = _nodeInfo_from nia
283− , _nodeInfo_to = _nodeInfo_to nib
285− applyFixup :: k a -> NodeInfo k p a -> Const (Fixup k p) a -> Maybe (NodeInfo k p a)
286− applyFixup _ ni (Const fixup) = case fixup of
287− Fixup_Delete -> Nothing
288− Fixup_Update u -> Just $ NodeInfo
289− { _nodeInfo_from = case _nodeInfo_from ni of
290− f@(From_Move ((between0 :: k between0) :=> Flip (p' :: p between0 a))) -> case getHere u of -- The `from` fixup comes from the "old" patch
291− Nothing -> f -- If there's no `from` fixup, just use the "new" `from`
292− Just ((between1 :: k between1) :=> frm) -> case geq between0 between1 of
293− Nothing -> error "fixup joined-on key did not match"
294− Just Refl -> case frm of
295− From_Insert v -> From_Insert $ applyAlwaysHet2 p' v
296− From_Delete -> From_Delete
297− From_Move (oldKey :=> Flip (p :: p oldKey between1)) -> From_Move $ oldKey :=> Flip (p' `o` p :: p oldKey a)
298− _ -> error "PatchMapWithPatchingMove: fixup for non-move From"
299− , _nodeInfo_to = fromMaybe (_nodeInfo_to ni) $ getThere u
301− m = DMap.differenceWithKey applyFixup (DMap.unionWithKey combineNodeInfos ma mb) fixups
302− getHere :: These a b -> Maybe a
307− getThere :: These a b -> Maybe b
313−-- | Compose patches having the same effect as applying the patches in turn:
314−-- @'applyAlways' (p <> q) == 'applyAlways' p . 'applyAlways' q@
315−instance ( GCompare k
316− , Cat.Semigroupoid p
317− , Cat.DecidablyEmpty p
319− , PatchSource1 p ~ PatchTarget1 p
320− ) => Monoid (PatchDMapWithPatchingMove k p) where
321− mempty = PatchDMapWithPatchingMove mempty
325−mappendPatchDMapWithPatchingMoveSlow :: forall k v. (ShowTag k v, GCompare k) => PatchDMapWithPatchingMove k v -> PatchDMapWithPatchingMove k v -> PatchDMapWithPatchingMove k v
326−PatchDMapWithPatchingMove dstAfter srcAfter `mappendPatchDMapWithPatchingMoveSlow` PatchDMapWithPatchingMove dstBefore srcBefore = PatchDMapWithPatchingMove dst src
328− getDstAction k m = fromMaybe (From_Move k) $ DMap.lookup k m -- Any key that isn't present is treated as that key moving to itself
329− removeRedundantDst toKey (From_Move fromKey) | isJust (toKey `geq` fromKey) = Nothing
330− removeRedundantDst _ a = Just a
331− f :: forall a. k a -> From k v a -> Maybe (From k v a)
332− f toKey _ = removeRedundantDst toKey $ case getDstAction toKey dstAfter of
333− From_Move fromKey -> getDstAction fromKey dstBefore
335− dst = DMap.mapMaybeWithKey f $ DMap.union dstAfter dstBefore
336− getSrcAction k m = fromMaybe (ComposeMaybe $ Just k) $ DMap.lookup k m
337− removeRedundantSrc fromKey (ComposeMaybe (Just toKey)) | isJust (fromKey `geq` toKey) = Nothing
338− removeRedundantSrc _ a = Just a
339− g :: forall a. k a -> ComposeMaybe k a -> Maybe (ComposeMaybe k a)
340− g fromKey _ = removeRedundantSrc fromKey $ case getSrcAction fromKey srcBefore of
341− ComposeMaybe Nothing -> ComposeMaybe Nothing
342− ComposeMaybe (Just toKeyBefore) -> getSrcAction toKeyBefore srcAfter
343− src = DMap.mapMaybeWithKey g $ DMap.union srcAfter srcBefore
346−-- | Make a @'PatchDMapWithPatchingMove' k v@ which has the effect of inserting or
347−-- updating a value @PatchTarget1 p a@ to the given key @k a@, like
349−insertDMapKey :: k a -> PatchTarget1 p a -> PatchDMapWithPatchingMove k p
351− PatchDMapWithPatchingMove . DMap.singleton k $ NodeInfo (From_Insert v) To_NonMove
353−-- | Make a @'PatchDMapWithPatchingMove' k v@ which has the effect of moving the value
354−-- from the first key @k a@ to the second key @k a@, equivalent to:
357−-- 'DMap.delete' src (maybe dmap ('DMap.insert' dst) (DMap.lookup src dmap))
361− => k a -> k a -> PatchDMapWithPatchingMove k (Proxy3 v)
362−moveDMapKey src dst = case src `geq` dst of
363− Nothing -> PatchDMapWithPatchingMove $ DMap.fromList
364− [ dst :=> NodeInfo (From_Move (src :=> Flip Proxy3)) To_NonMove
365− , src :=> NodeInfo From_Delete (To_Move $ Some dst)
367− Just _ -> PatchDMapWithPatchingMove DMap.empty
369−-- | Make a @'PatchDMapWithPatchingMove' k v@ which has the effect of swapping two keys
370−-- in the mapping, equivalent to:
373−-- let aMay = DMap.lookup a dmap
374−-- bMay = DMap.lookup b dmap
375−-- in maybe id (DMap.insert a) (bMay <> aMay)
376−-- . maybe id (DMap.insert b) (aMay <> bMay)
377−-- . DMap.delete a . DMap.delete b $ dmap
379−swapDMapKey :: GCompare k => k a -> k a -> PatchDMapWithPatchingMove k (Proxy3 v)
380−swapDMapKey src dst = case src `geq` dst of
381− Nothing -> PatchDMapWithPatchingMove $ DMap.fromList
382− [ dst :=> NodeInfo (From_Move (src :=> Flip Proxy3)) (To_Move $ Some src)
383− , src :=> NodeInfo (From_Move (dst :=> Flip Proxy3)) (To_Move $ Some dst)
385− Just _ -> PatchDMapWithPatchingMove DMap.empty
387−-- | Make a @'PatchDMapWithPatchingMove' k v@ which has the effect of deleting a key in
388−-- the mapping, equivalent to 'DMap.delete'.
389−deleteDMapKey :: k a -> PatchDMapWithPatchingMove k v
390−deleteDMapKey k = PatchDMapWithPatchingMove $ DMap.singleton k $ NodeInfo From_Delete To_NonMove
393−k1, k2 :: Const2 Int () ()
396−p1, p2 :: PatchDMapWithPatchingMove (Const2 Int ()) Identity
397−p1 = moveDMapKey k1 k2
398−p2 = moveDMapKey k2 k1
401−p12Slow = p1 `mappendPatchDMapWithPatchingMoveSlow` p2
402−p21Slow = p2 `mappendPatchDMapWithPatchingMoveSlow` p1
404−testPatchDMapWithPatchingMove = do
407− print $ p12 == deleteDMapKey k1
408− print $ p21 == deleteDMapKey k2
409− print $ p12Slow == deleteDMapKey k1
410− print $ p21Slow == deleteDMapKey k2
412−dst (PatchDMapWithPatchingMove x _) = x
413−src (PatchDMapWithPatchingMove _ x) = x
416−-- | Extract the 'DMap' representing the patch changes from the
417−-- 'PatchDMapWithPatchingMove'.
418−unPatchDMapWithPatchingMove :: PatchDMapWithPatchingMove k v -> DMap k (NodeInfo k v)
419−unPatchDMapWithPatchingMove (PatchDMapWithPatchingMove p) = p
421−-- | Wrap a 'DMap' representing patch changes into a 'PatchDMapWithPatchingMove',
422−-- without checking any invariants.
424−-- __Warning:__ when using this function, you must ensure that the invariants of 'PatchDMapWithPatchingMove' are preserved; they will not be checked.
425−unsafePatchDMapWithPatchingMove :: DMap k (NodeInfo k v) -> PatchDMapWithPatchingMove k v
426−unsafePatchDMapWithPatchingMove = PatchDMapWithPatchingMove
428−-- | Wrap a 'DMap' representing patch changes into a 'PatchDMapWithPatchingMove' while
429−-- checking invariants. If the invariants are satisfied, @Right p@ is returned
430−-- otherwise @Left errors@.
431−patchDMapWithPatchingMove :: (GCompare k, GShow k) => DMap k (NodeInfo k v) -> Either [String] (PatchDMapWithPatchingMove k v)
432−patchDMapWithPatchingMove dm =
433− case validationErrorsForPatchDMapWithPatchingMove dm of
434− [] -> Right $ unsafePatchDMapWithPatchingMove dm
437−-- | Map a natural transform @v -> v'@ over the given patch, transforming
438−-- @'PatchDMapWithPatchingMove' k v@ into @'PatchDMapWithPatchingMove' k v'@.
439−mapPatchDMapWithPatchingMove
441− . (forall a. PatchTarget1 p a -> PatchTarget1 p' a)
442− -> (forall from to. p from to -> p' from to)
443− -> PatchDMapWithPatchingMove k p
444− -> PatchDMapWithPatchingMove k p'
445−mapPatchDMapWithPatchingMove f g (PatchDMapWithPatchingMove m) =
446− PatchDMapWithPatchingMove $ DMap.map (\ni -> NodeInfo
447− { _nodeInfo_from = h $ _nodeInfo_from ni
448− , _nodeInfo_to = _nodeInfo_to ni
450− where h :: forall a. From k p a -> From k p' a
452− From_Insert v -> From_Insert $ f v
453− From_Delete -> From_Delete
454− From_Move (k :=> Flip p) -> From_Move $ k :=> Flip (g p)
456−-- | Traverse an effectful function @forall a. PatchTarget1 p a -> m (v ' a)@
457−-- over the given patch, transforming @'PatchDMapWithPatchingMove' k v@ into @m
458−-- ('PatchDMapWithPatchingMove' k v')@.
459−traversePatchDMapWithPatchingMove
462− => (forall a. PatchTarget1 p a -> m (PatchTarget1 p' a))
463− -> (forall from to. p from to -> m (p' from to))
464− -> PatchDMapWithPatchingMove k p
465− -> m (PatchDMapWithPatchingMove k p')
466−traversePatchDMapWithPatchingMove f g = traversePatchDMapWithPatchingMoveWithKey
470−-- | Map an effectful function @forall a. k a -> PatchTarget1 p a -> m (v ' a)@
471−-- over the given patch, transforming @'PatchDMapWithPatchingMove' k v@ into @m
472−-- ('PatchDMapWithPatchingMove' k v')@.
473−traversePatchDMapWithPatchingMoveWithKey
476− => (forall a. k a -> PatchTarget1 p a -> m (PatchTarget1 p' a))
477− -> (forall from to. k from -> k to -> p from to -> m (p' from to))
478− -> PatchDMapWithPatchingMove k p
479− -> m (PatchDMapWithPatchingMove k p')
480−traversePatchDMapWithPatchingMoveWithKey f g (PatchDMapWithPatchingMove m) =
481− PatchDMapWithPatchingMove <$> DMap.traverseWithKey (\k ni -> NodeInfo
482− <$> h k (_nodeInfo_from ni)
483− <*> pure (_nodeInfo_to ni)) m
484− where h :: forall a. k a -> From k p a -> m (From k p' a)
486− From_Insert v -> From_Insert <$> f k v
487− From_Delete -> pure From_Delete
488− From_Move (fromKey :=> Flip p) -> From_Move . (fromKey :=>) . Flip <$> g fromKey k p
490−-- | Map a function which transforms @'From k PatchTarget1 p a@ into a @'From k
491−-- PatchTarget1 p' a@ over a @'NodeInfo' k PatchTarget1 p a@.
493− :: (From k p a -> From k p' a)
497−nodeInfoMapFrom f g ni = NodeInfo
498− { _nodeInfo_from = f $ _nodeInfo_from ni
499− , _nodeInfo_to = g $ _nodeInfo_to ni
502−-- | Map an effectful function which transforms @'From k PatchTarget1 p a@ into
503−-- a @f ('From k PatchTarget1 p' a)@ over a @'NodeInfo' k PatchTarget1 p a@.
506− => (From k p a -> f (From k p' a))
507− -> (To k -> f (To k))
509− -> f (NodeInfo k p' a)
510−nodeInfoMapFromM f g ni = NodeInfo
511− <$> f (_nodeInfo_from ni)
512− <*> g (_nodeInfo_to ni)
514−-- | Weaken a 'PatchDMapWithPatchingMove' to a 'PatchMapWithPatchingMove' by weakening the keys
515−-- from @k a@ to @'Some' k@ and applying a given weakening function
516−-- @PatchTarget1 p a -> v'@ to values.
517−weakenPatchDMapWithPatchingMoveWith
519− . (forall a. PatchTarget1 p a -> PatchTarget p')
520− -> (forall from to. p from to -> p')
521− -> PatchDMapWithPatchingMove k p
522− -> PatchMapWithPatchingMove (Some k) p'
523−weakenPatchDMapWithPatchingMoveWith f g (PatchDMapWithPatchingMove m) =
524− PatchMapWithPatchingMove $ weakenDMapWith h m
525− where h :: forall a. NodeInfo k p a -> MapWithPatchingMove.NodeInfo (Some k) p'
526− h ni = MapWithPatchingMove.NodeInfo
527− { MapWithPatchingMove._nodeInfo_from = case _nodeInfo_from ni of
528− From_Insert v -> MapWithPatchingMove.From_Insert $ f v
529− From_Delete -> MapWithPatchingMove.From_Delete
530− From_Move (k :=> Flip p) -> MapWithPatchingMove.From_Move (mkSome k) $ g p
531− , MapWithPatchingMove._nodeInfo_to = case _nodeInfo_to ni of
532− To_NonMove -> Nothing
533− To_Move (Some k) -> Just (mkSome k)
536−-- | "Weaken" a @'PatchDMapWithPatchingMove' (Const2 k a) v@ to a @'PatchMapWithPatchingMove' k
537−-- v'@. Weaken is in scare quotes because the 'Const2' has already disabled any
538−-- dependency in the typing and all points are already @a@, hence the function
539−-- to map each value to @v'@ is not higher rank.
540−patchDMapWithPatchingMoveToPatchMapWithPatchingMoveWith
542− . (PatchTarget1 p a -> PatchTarget p')
544− -> PatchDMapWithPatchingMove (Const2 k a) p
545− -> PatchMapWithPatchingMove k p'
546−patchDMapWithPatchingMoveToPatchMapWithPatchingMoveWith f g (PatchDMapWithPatchingMove m) =
547− PatchMapWithPatchingMove $ dmapToMapWith h m
548− where h :: NodeInfo (Const2 k a) p a -> MapWithPatchingMove.NodeInfo k p'
549− h ni = MapWithPatchingMove.NodeInfo
550− { MapWithPatchingMove._nodeInfo_from = case _nodeInfo_from ni of
551− From_Insert v -> MapWithPatchingMove.From_Insert $ f v
552− From_Delete -> MapWithPatchingMove.From_Delete
553− From_Move (Const2 k :=> Flip p) -> MapWithPatchingMove.From_Move k $ g p
554− , MapWithPatchingMove._nodeInfo_to = case _nodeInfo_to ni of
555− To_NonMove -> Nothing
556− To_Move (Some (Const2 k)) -> Just k
559−-- | "Strengthen" a @'PatchMapWithPatchingMove' k v@ into a @'PatchDMapWithPatchingMove
560−-- ('Const2' k a)@; that is, turn a non-dependently-typed patch into a
561−-- dependently typed one but which always has a constant key type represented by
562−-- 'Const2'. Apply the given function to each @v@ to produce a @PatchTarget1 p'
563−-- a@. Completemented by 'patchDMapWithPatchingMoveToPatchMapWithPatchingMoveWith'
564−const2PatchDMapWithPatchingMoveWith
567− -> PatchMapWithPatchingMove k (Proxy v)
568− -> PatchDMapWithPatchingMove (Const2 k a) (Proxy3 v')
569−const2PatchDMapWithPatchingMoveWith f (PatchMapWithPatchingMove p) =
570− PatchDMapWithPatchingMove $ DMap.fromDistinctAscList $ g <$> Map.toAscList p
571− where g :: (k, MapWithPatchingMove.NodeInfo k (Proxy v))
572− -> DSum (Const2 k a) (NodeInfo (Const2 k a) (Proxy3 v'))
573− g (k, ni) = Const2 k :=> NodeInfo
574− { _nodeInfo_from = case MapWithPatchingMove._nodeInfo_from ni of
575− MapWithPatchingMove.From_Insert v -> From_Insert $ f v
576− MapWithPatchingMove.From_Delete -> From_Delete
577− MapWithPatchingMove.From_Move fromKey Proxy -> From_Move $ Const2 fromKey :=> Flip Proxy3
578− , _nodeInfo_to = case MapWithPatchingMove._nodeInfo_to ni of
579− Nothing -> To_NonMove
580− Just toKey -> To_Move $ Some (Const2 toKey)
583−-- | Apply the insertions, deletions, and moves to a given 'DMap'.
584−instance ( GCompare k
586− , PatchSource1 p ~ PatchTarget1 p
587− ) => PatchHet (PatchDMapWithPatchingMove k p) where
588− type PatchSource (PatchDMapWithPatchingMove k p) = DMap k (PatchSource1 p)
589− type PatchTarget (PatchDMapWithPatchingMove k p) = DMap k (PatchTarget1 p)
591−instance ( GCompare k
593− , PatchSource1 p ~ PatchTarget1 p
594− ) => Patch (PatchDMapWithPatchingMove k p) where
595− apply (PatchDMapWithPatchingMove m) old = Just $! insertions `DMap.union` (old `DMap.difference` deletions)
596− -- TODO: return Nothing sometimes --Note: the strict application here is
597− -- critical to ensuring that incremental merges don't hold onto all their
598− -- prerequisite events forever; can we make this more robust?
599− where insertions = DMap.mapMaybeWithKey insertFunc m
600− insertFunc :: forall a. k a -> NodeInfo k p a -> Maybe (PatchTarget1 p a)
601− insertFunc _ ni = case _nodeInfo_from ni of
602− From_Insert v -> Just v
603− From_Move (k :=> Flip p) -> applyAlwaysHet2 p <$> DMap.lookup k old
604− From_Delete -> Nothing
605− deletions = DMap.mapMaybeWithKey deleteFunc m
606− deleteFunc :: forall a. k a -> NodeInfo k p a -> Maybe (Constant () a)
607− deleteFunc _ ni = case _nodeInfo_from ni of
608− From_Delete -> Just $ Constant ()
611−-- | Get the values that will be replaced, deleted, or moved if the given patch
612−-- is applied to the given 'DMap'.
615− , PatchSource1 p ~ PatchTarget1 p
617− => PatchDMapWithPatchingMove k p
618− -> DMap k (PatchSource1 p)
619− -> DMap k (Product (PatchTarget1 p) (Const (To k)))
620−getDeletionsAndMoves (PatchDMapWithPatchingMove p) m = DMap.intersectionWithKey f m p
621− where f _ v ni = Pair v $ Const $ _nodeInfo_to ni