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mirror of https://github.com/github/semantic.git synced 2024-12-24 15:35:14 +03:00

Index the diffs.

This commit is contained in:
Rob Rix 2016-07-05 14:57:11 -04:00
parent 94ccb9737d
commit 1323455da4

View File

@ -20,29 +20,29 @@ import Test.QuickCheck hiding (Fixed)
import Test.QuickCheck.Random import Test.QuickCheck.Random
-- | Given a function comparing two terms recursively, and a function to compute a Hashable label from an annotation, compute the diff of a pair of lists of terms using a random walk similarity metric, which completes in log-linear time. This implementation is based on the paper [_RWS-Diff—Flexible and Efficient Change Detection in Hierarchical Data_](https://github.com/github/semantic-diff/files/325837/RWS-Diff.Flexible.and.Efficient.Change.Detection.in.Hierarchical.Data.pdf). -- | Given a function comparing two terms recursively, and a function to compute a Hashable label from an annotation, compute the diff of a pair of lists of terms using a random walk similarity metric, which completes in log-linear time. This implementation is based on the paper [_RWS-Diff—Flexible and Efficient Change Detection in Hierarchical Data_](https://github.com/github/semantic-diff/files/325837/RWS-Diff.Flexible.and.Efficient.Change.Detection.in.Hierarchical.Data.pdf).
rws :: (Hashable label, Hashable leaf, Eq leaf, Ord annotation) => (Term leaf annotation -> Term leaf annotation -> Maybe (Diff leaf annotation)) -> (annotation -> label) -> [Term leaf annotation] -> [Term leaf annotation] -> [Diff leaf annotation] rws :: (Hashable label, Hashable leaf, Eq leaf, Eq annotation) => (Term leaf annotation -> Term leaf annotation -> Maybe (Diff leaf annotation)) -> (annotation -> label) -> [Term leaf annotation] -> [Term leaf annotation] -> [Diff leaf annotation]
rws compare getLabel as bs rws compare getLabel as bs
| null as, null bs = [] | null as, null bs = []
| null as = insert <$> bs | null as = insert <$> bs
| null bs = delete <$> as | null bs = delete <$> as
| otherwise = uncurry deleteRemaining . (`runState` fas) $ traverse findNearestNeighbourTo fbs | otherwise = fmap snd . uncurry deleteRemaining . (`runState` fas) $ traverse findNearestNeighbourTo fbs
where insert = pure . Insert where insert = pure . Insert
delete = pure . Delete delete = pure . Delete
replace = (pure .) . Replace replace = (pure .) . Replace
(p, q, d) = (2, 2, 15) (p, q, d) = (2, 2, 15)
fas = featurize <$> as fas = zip [0..] (featurize <$> as)
fbs = featurize <$> bs fbs = zip [0..] (featurize <$> bs)
kdas = KdTree.build (Vector.toList . fst) fas kdas = KdTree.build (Vector.toList . fst . snd) fas
featurize = featureVector d . pqGrams p q getLabel &&& identity featurize = featureVector d . pqGrams p q getLabel &&& identity
findNearestNeighbourTo kv@(_, v) = do findNearestNeighbourTo kv@(_, (_, v)) = do
unmapped <- get unmapped <- get
let (k, _) = KdTree.nearest kdas kv let (i, (k, _)) = KdTree.nearest kdas kv
case k `List.lookup` unmapped of case i `List.lookup` unmapped of
Nothing -> pure $! insert v Nothing -> pure (negate 1, insert v)
Just found -> do Just (k, found) -> do
put (List.delete (k, found) unmapped) put (List.delete (i, (k, found)) unmapped)
pure $! fromMaybe (replace found v) (compare found v) pure (negate 1, fromMaybe (replace found v) (compare found v))
deleteRemaining diffs unmapped = foldl' (flip (List.insertBy (comparing firstAnnotation))) diffs (delete . snd <$> unmapped) deleteRemaining diffs unmapped = foldl' (flip (List.insertBy (comparing fst))) diffs (second (delete . snd) <$> unmapped)
-- | Extract the annotation for the before state of a diff node. This is returned in `Maybe` because e.g. an `Insert` patch does not have an annotation for the before state. -- | Extract the annotation for the before state of a diff node. This is returned in `Maybe` because e.g. an `Insert` patch does not have an annotation for the before state.
firstAnnotation :: Diff leaf annotation -> Maybe annotation firstAnnotation :: Diff leaf annotation -> Maybe annotation