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1+{-# LANGUAGE CPP #-}
2+{-# LANGUAGE ConstraintKinds #-}
3+{-# LANGUAGE FlexibleContexts #-}
4+{-# LANGUAGE FlexibleInstances #-}
5+{-# LANGUAGE GADTs #-}
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 #-}
17+
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
21+
22+import qualified Control.Category as Cat
23+import qualified Control.Category.DecidablyEmpty as Cat
24+
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 (..)
32+ , weakenDMapWith
33+ , dmapToMapWith
34+ )
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
40+import Data.Maybe
41+import Data.Monoid.DecidablyEmpty
42+import Data.Semigroupoid as Cat
43+#if !MIN_VERSION_base(4,11,0)
44+import Data.Semigroup (Semigroup (..), (<>))
45+#endif
46+import Data.Some (Some (Some), mkSome)
47+import Data.Proxy (Proxy (..))
48+import Data.These (These (..))
49+import Data.Type.Equality ((:~:)(..))
50+
51+import Data.Patch.Class
52+ ( Patch (..), PatchHet (..)
53+ , PatchHet2 (..), PatchSource1, PatchTarget1
54+ , applyAlwaysHet2
55+ )
56+import Data.Patch.MapWithPatchingMove (PatchMapWithPatchingMove (..))
57+import qualified Data.Patch.MapWithPatchingMove as MapWithPatchingMove
58+
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
61+-- and destinations.
62+--
63+-- Invariants:
64+--
65+-- * A key should not move to itself.
66+--
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'
69+-- destination)@)
70+newtype PatchDMapWithPatchingMove k v = PatchDMapWithPatchingMove (DMap k (NodeInfo k v))
71+
72+--deriving instance ( GShow k
73+-- , HasZip Show k p
74+-- , Has' Show k (PatchTarget1 p)
75+-- ) => Show (PatchDMapWithPatchingMove k p)
76+--deriving instance ( GRead k
77+-- , HasZip Read k p
78+-- , Has' Read k (PatchTarget1 p)
79+-- ) => Read (PatchDMapWithPatchingMove k p)
80+--deriving instance ( GEq k
81+-- , HasZip Eq k p
82+-- , Has' Eq k (PatchTarget1 p)
83+-- ) => Eq (PatchDMapWithPatchingMove k p)
84+--deriving instance ( GCompare k
85+-- , HasZip Ord k p
86+-- , Has' Ord k (PatchTarget1 p)
87+-- ) => Ord (PatchDMapWithPatchingMove k p)
88+
89+-- It won't let me derive for some reason
90+instance ( GCompare k
91+ , Cat.DecidablyEmpty v
92+ , Cat.Semigroupoid v
93+ , PatchHet2 v
94+ , PatchSource1 v ~ PatchTarget1 v
95+ ) => DecidablyEmpty (PatchDMapWithPatchingMove k v) where
96+ isEmpty (PatchDMapWithPatchingMove m) = DMap.null m
97+
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'.
108+ }
109+
110+--deriving instance ( Show (k a)
111+-- , Show (p a a)
112+-- , Show (PatchTarget1 p a)
113+-- ) => Show (NodeInfo k p a)
114+--deriving instance ( Read (k a)
115+-- , Read (p a a)
116+-- , Read (PatchTarget1 p a)
117+-- ) => Read (NodeInfo k p a)
118+--deriving instance ( Eq (k a)
119+-- , Eq (p a a)
120+-- , Eq (PatchTarget1 p a)
121+-- ) => Eq (NodeInfo k p a)
122+--deriving instance ( Ord (k a)
123+-- , Ord (p a a)
124+-- , Ord (PatchTarget1 p a)
125+-- ) => Ord (NodeInfo k p a)
126+
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@).
130+--
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
136+ -- p a@
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
144+
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)
162+
163+newtype Flip p to from = Flip (p from to)
164+
165+instance Cat.Category p => Cat.Category (Flip (p :: k -> k -> *)) where
166+ id = Flip Cat.id
167+ Flip y . Flip x = Flip $ x Cat.. y
168+
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
174+ To_NonMove :: To k
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
179+
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)
184+
185+-- |Test whether a 'PatchDMapWithPatchingMove' satisfies its invariants.
186+validPatchDMapWithPatchingMove
187+ :: forall k v
188+ . (GCompare k, GShow k)
189+ => DMap k (NodeInfo k v)
190+ -> Bool
191+validPatchDMapWithPatchingMove = not . null . validationErrorsForPatchDMapWithPatchingMove
192+
193+-- |Enumerate what reasons a 'PatchDMapWithPatchingMove' doesn't satisfy its invariants, returning @[]@ if it's valid.
194+validationErrorsForPatchDMapWithPatchingMove
195+ :: forall k v
196+ . (GCompare k, GShow k)
197+ => DMap k (NodeInfo k v)
198+ -> [String]
199+validationErrorsForPatchDMapWithPatchingMove m =
200+ noSelfMoves <> movesBalanced
201+ where
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"
215+ else Nothing
216+ _ ->
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"
224+ else Nothing
225+
226+ _ ->
227+ Just $ "unbalanced move at source key " <> gshow src <> " supposedly going to " <> gshow dst <> " but destination key is not moving"
228+ unbalancedMove _ = Nothing
229+
230+
231+data ToFrom k p a = ToFrom (To k) (From k p a)
232+
233+-- | Helper data structure used for composing patches using the monoid instance.
234+data Fixup k p
235+ = Fixup_Delete
236+ | Fixup_Update (These (DSum k (From k p)) (To k))
237+
238+-- | Compose patches having the same effect as applying the patches in turn:
239+-- @'applyAlways' (p <> q) == 'applyAlways' p . 'applyAlways' q@
240+instance forall k p
241+ . ( GCompare k
242+ , Cat.Semigroupoid p
243+ , Cat.DecidablyEmpty p
244+ , PatchHet2 p
245+ , PatchSource1 p ~ PatchTarget1 p
246+ )
247+ => Semigroup (PatchDMapWithPatchingMove k p) where
248+ PatchDMapWithPatchingMove ma <> PatchDMapWithPatchingMove mb = PatchDMapWithPatchingMove m
249+ where
250+ connections :: [DSum k (ToFrom k p)]
251+ connections = DMap.toList $ DMap.intersectionWithKey
252+ (\_ a b -> ToFrom (_nodeInfo_to a) (_nodeInfo_from b))
253+ ma
254+ mb
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) ->
258+ case Cat.isId p of
259+ Just Refl ->
260+ [ toAfter :=> Const Fixup_Delete ]
261+ Nothing ->
262+ [ toAfter :=> Const (Fixup_Update $ This $ between :=> From_Move (fromBefore :=> Flip p))
263+ , fromBefore :=> Const (Fixup_Update $ That $ To_Move $ Some toAfter)
264+ ]
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)]
271+ (To_NonMove, _) ->
272+ []
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
284+ }
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
300+ }
301+ m = DMap.differenceWithKey applyFixup (DMap.unionWithKey combineNodeInfos ma mb) fixups
302+ getHere :: These a b -> Maybe a
303+ getHere = \case
304+ This a -> Just a
305+ These a _ -> Just a
306+ That _ -> Nothing
307+ getThere :: These a b -> Maybe b
308+ getThere = \case
309+ This _ -> Nothing
310+ These _ b -> Just b
311+ That b -> Just b
312+
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
318+ , PatchHet2 p
319+ , PatchSource1 p ~ PatchTarget1 p
320+ ) => Monoid (PatchDMapWithPatchingMove k p) where
321+ mempty = PatchDMapWithPatchingMove mempty
322+ mappend = (<>)
323+
324+{-
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
327+ where
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
334+ nonMove -> nonMove
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
344+-}
345+
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
348+-- 'DMap.insert'.
349+insertDMapKey :: k a -> PatchTarget1 p a -> PatchDMapWithPatchingMove k p
350+insertDMapKey k v =
351+ PatchDMapWithPatchingMove . DMap.singleton k $ NodeInfo (From_Insert v) To_NonMove
352+
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:
355+--
356+-- @
357+-- 'DMap.delete' src (maybe dmap ('DMap.insert' dst) (DMap.lookup src dmap))
358+-- @
359+moveDMapKey
360+ :: GCompare k
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)
366+ ]
367+ Just _ -> PatchDMapWithPatchingMove DMap.empty
368+
369+-- | Make a @'PatchDMapWithPatchingMove' k v@ which has the effect of swapping two keys
370+-- in the mapping, equivalent to:
371+--
372+-- @
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
378+-- @
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)
384+ ]
385+ Just _ -> PatchDMapWithPatchingMove DMap.empty
386+
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
391+
392+{-
393+k1, k2 :: Const2 Int () ()
394+k1 = Const2 1
395+k2 = Const2 2
396+p1, p2 :: PatchDMapWithPatchingMove (Const2 Int ()) Identity
397+p1 = moveDMapKey k1 k2
398+p2 = moveDMapKey k2 k1
399+p12 = p1 <> p2
400+p21 = p2 <> p1
401+p12Slow = p1 `mappendPatchDMapWithPatchingMoveSlow` p2
402+p21Slow = p2 `mappendPatchDMapWithPatchingMoveSlow` p1
403+
404+testPatchDMapWithPatchingMove = do
405+ print p1
406+ print p2
407+ print $ p12 == deleteDMapKey k1
408+ print $ p21 == deleteDMapKey k2
409+ print $ p12Slow == deleteDMapKey k1
410+ print $ p21Slow == deleteDMapKey k2
411+
412+dst (PatchDMapWithPatchingMove x _) = x
413+src (PatchDMapWithPatchingMove _ x) = x
414+-}
415+
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
420+
421+-- | Wrap a 'DMap' representing patch changes into a 'PatchDMapWithPatchingMove',
422+-- without checking any invariants.
423+--
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
427+
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
435+ errs -> Left errs
436+
437+-- | Map a natural transform @v -> v'@ over the given patch, transforming
438+-- @'PatchDMapWithPatchingMove' k v@ into @'PatchDMapWithPatchingMove' k v'@.
439+mapPatchDMapWithPatchingMove
440+ :: forall k p p'
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
449+ }) m
450+ where h :: forall a. From k p a -> From k p' a
451+ h = \case
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)
455+
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
460+ :: forall m k p p'
461+ . Applicative m
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
467+ (\_ -> f)
468+ (\_ _ -> g)
469+
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
474+ :: forall m k p p'
475+ . Applicative m
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)
485+ h k = \case
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
489+
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@.
492+nodeInfoMapFrom
493+ :: (From k p a -> From k p' a)
494+ -> (To k -> To k)
495+ -> NodeInfo k p a
496+ -> NodeInfo k p' a
497+nodeInfoMapFrom f g ni = NodeInfo
498+ { _nodeInfo_from = f $ _nodeInfo_from ni
499+ , _nodeInfo_to = g $ _nodeInfo_to ni
500+ }
501+
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@.
504+nodeInfoMapFromM
505+ :: Applicative f
506+ => (From k p a -> f (From k p' a))
507+ -> (To k -> f (To k))
508+ -> NodeInfo k p a
509+ -> f (NodeInfo k p' a)
510+nodeInfoMapFromM f g ni = NodeInfo
511+ <$> f (_nodeInfo_from ni)
512+ <*> g (_nodeInfo_to ni)
513+
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
518+ :: forall k p p'
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)
534+ }
535+
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
541+ :: forall k p p' a
542+ . (PatchTarget1 p a -> PatchTarget p')
543+ -> (p a a -> 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
557+ }
558+
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
565+ :: forall k v v' a
566+ . (v -> v' a)
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)
581+ }
582+
583+-- | Apply the insertions, deletions, and moves to a given 'DMap'.
584+instance ( GCompare k
585+ , PatchHet2 p
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)
590+
591+instance ( GCompare k
592+ , PatchHet2 p
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 ()
609+ _ -> Nothing
610+
611+-- | Get the values that will be replaced, deleted, or moved if the given patch
612+-- is applied to the given 'DMap'.
613+getDeletionsAndMoves
614+ :: ( GCompare k
615+ , PatchSource1 p ~ PatchTarget1 p
616+ )
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