interval-algebra-0.8.6: src/IntervalAlgebra/IntervalUtilities.hs
{-|
Module : Interval Algebra Utilities
Description : Functions for operating on containers of Intervals.
Copyright : (c) NoviSci, Inc 2020
License : BSD3
Maintainer : bsaul@novisci.com
Stability : experimental
In the examples below, @iv@ is a synonym for 'beginerval' used to save space.
-}
{-# LANGUAGE Safe #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE FlexibleInstances #-}
module IntervalAlgebra.IntervalUtilities (
-- * Fold over sequential intervals
combineIntervals
, combineIntervalsL
, gaps
, gapsL
, gapsWithin
-- * Operations on Meeting sequences of paired intervals
, foldMeetingSafe
, formMeetingSequence
-- * Withering functions
-- ** Clear containers based on predicate
, nothingIf
, nothingIfNone
, nothingIfAny
, nothingIfAll
-- ** Filter containers based on predicate
, filterBefore
, filterMeets
, filterOverlaps
, filterFinishedBy
, filterContains
, filterStarts
, filterEquals
, filterStartedBy
, filterDuring
, filterFinishes
, filterOverlappedBy
, filterMetBy
, filterAfter
, filterDisjoint
, filterNotDisjoint
, filterConcur
, filterWithin
, filterEnclose
, filterEnclosedBy
-- * Misc utilities
, relations
, relationsL
, intersect
, clip
, durations
) where
import safe GHC.Show ( Show )
import safe GHC.Int ( Int )
import safe Control.Applicative ( Applicative(pure)
, (<*>) )
import qualified Control.Foldl as L
import safe Control.Monad ( Functor(fmap) )
import safe Data.Bool ( Bool, otherwise, not, (||), (&&) )
import safe Data.Eq ( Eq((==)) )
import safe Data.Foldable ( Foldable(null, foldl', toList)
, all
, any
, or )
import safe Data.Function ( ($), (.), flip )
import safe Data.Monoid ( Monoid(mempty) )
import safe Data.Maybe ( Maybe(..)
, maybe
, maybeToList )
import safe Data.Ord ( Ord(min, max) )
import safe Data.Semigroup ( Semigroup((<>)) )
import safe Data.Traversable ( Traversable(sequenceA) )
import safe Data.Tuple ( fst )
import safe Safe ( headMay, lastMay, initSafe, tailSafe)
import safe Witherable ( Filterable(filter)
, Witherable(..)
, mapMaybe
, catMaybes )
import safe IntervalAlgebra ( (<|>),
begin,
end,
after,
before,
beginerval,
beginervalFromEnd,
endervalFromBegin,
concur,
contains,
disjoint,
during,
enclose,
enclosedBy,
enderval,
equals,
extenterval,
finishedBy,
finishes,
meets,
metBy,
notDisjoint,
overlappedBy,
overlaps,
relate,
startedBy,
starts,
within,
ComparativePredicateOf1,
ComparativePredicateOf2,
Interval,
IntervalCombinable((<+>), (><)),
IntervalRelation(..),
IntervalSizeable(diff, duration),
Intervallic(..) )
import safe IntervalAlgebra.PairedInterval
( PairedInterval
, makePairedInterval
, getPairData
, equalPairData )
-------------------------------------------------
-- Unexported utilties used in functions below --
-------------------------------------------------
-- Just a synonym used to examples to save typing
iv :: Int -> Int -> Interval Int
iv = beginerval
-- An internal utility function for creating a @Fold@ that maps over a structure
-- by consecutive pairs into a new structure.
makeFolder :: (Monoid (m b), Applicative m) =>
(a -> a -> b)
-> L.Fold a (m b)
makeFolder f = L.Fold step begin done
where
begin = (mempty, Nothing)
step (fs, Nothing) y = (fs, Just y)
step (fs, Just x) y = (fs <> pure (f x y), Just y)
done (fs, _) = fs
-- Used to combine two lists by combining the last element of @x@ and the first
-- element of @y@ by @f@. The combining function @f@ will generally return a
-- singleton list in the case that the last of x and head of y can be combined
-- or a two element list in the case they cannot.
listCombiner :: (Maybe a -> Maybe a -> [a]) -- ^ f
-> [a] -- ^ x
-> [a] -- ^ y
-> [a]
listCombiner f x y = initSafe x <> f (lastMay x) (headMay y) <> tailSafe y
-- | Returns a list of the 'IntervalRelation' between each consecutive pair
-- of intervals. This is just a specialized 'relations' which returns a list.
--
-- >>> relationsL [iv 1 0, iv 1 1]
-- [Meets]
relationsL :: (Foldable f, Intervallic i a )=>
f (i a)
-> [IntervalRelation]
relationsL = relations
-- | A generic form of 'relations' which can output any 'Applicative' and
-- 'Monoid' structure.
-- >>> (relations [iv 1 0, iv 1 1]) :: [IntervalRelation (Interval Int)]
-- [Meets]
--
relations :: ( Foldable f
, Applicative m
, Intervallic i a
, Monoid (m IntervalRelation ))=>
f (i a)
-> m IntervalRelation
relations = L.fold (makeFolder relate)
-- | Forms a 'Just' new interval from the intersection of two intervals,
-- provided the intervals are not disjoint.
--
-- >>> intersect (iv 5 0) (iv 2 3)
-- Just (3, 5)
intersect :: (Intervallic i a, IntervalSizeable a b) =>
i a -> i a -> Maybe (Interval a)
intersect x y
| disjoint x y = Nothing
| otherwise = Just $ beginerval (diff e b) b
where b = max (begin x) (begin y)
e = min (end x) (end y)
-- Internal function which folds over a structure by consecutive pairs, returing
-- gaps between each pair (@Nothing@ if no such gap exists).
gapsM:: ( IntervalCombinable i a
, Traversable f
, Monoid (f (Maybe (Interval a)))
, Applicative f) =>
f (i a) ->
f (Maybe (Interval a))
gapsM = L.fold (makeFolder (\i j -> getInterval i >< getInterval j))
-- | Returns a @Maybe@ container of intervals consisting of the gaps
-- between intervals in the input. *To work properly, the input should be
-- sorted*. See 'gapsL' for a version that always returns a list.
--
-- >>> gaps [iv 4 1, iv 4 8, iv 3 11]
--
gaps:: ( IntervalCombinable i a
, Traversable f
, Monoid (f (Maybe (Interval a)))
, Applicative f) =>
f (i a) ->
Maybe (f (Interval a))
gaps = sequenceA.gapsM
-- | Returns a (possibly empty) list of intervals consisting of the gaps between
-- intervals in the input container. *To work properly, the input should be
-- sorted*. This version outputs a list. See 'gaps' for a version that lifts
-- the result to same input structure @f@.
gapsL :: ( IntervalCombinable i a
, Applicative f
, Monoid (f (Maybe (Interval a)))
, Traversable f) =>
f (i a) ->
[Interval a]
gapsL x = maybe [] toList (gaps x)
-- | Returns the 'duration' of each 'Intervallic i a' in the 'Functor' @f@.
--
-- >>> durations [iv 9 1, iv 10 2, iv 1 5]
-- [9,10,1]
durations :: (Functor f, Intervallic i a, IntervalSizeable a b)=>
f (i a)
-> f b
durations = fmap duration
-- | In the case that x y are not disjoint, clips y to the extent of x.
--
-- >>> clip (iv 5 0) (iv 3 3)
-- Just (3, 5)
--
-- >>> clip (iv 3 0) (iv 2 4)
-- Nothing
clip :: (Intervallic i0 a, Intervallic i1 a, IntervalSizeable a b)=>
i0 a
-> i1 a
-> Maybe (Interval a)
clip x y
| overlaps x y = Just $ enderval (diff (end x) (begin y)) (end x)
| overlappedBy x y = Just $ beginerval (diff (end y) (begin x)) (begin x)
| jx x y = Just (getInterval x)
| jy x y = Just (getInterval y)
| otherwise = Nothing {- disjoint x y case -}
where jy = equals <|> startedBy <|> contains <|> finishedBy
jx = starts <|> during <|> finishes
-- | Applies 'gaps' to all the non-disjoint intervals in @x@ that are *not* disjoint
-- from @i@. Intervals that 'overlaps' or are 'overlappedBy' @i@ are 'clip'ped
-- to @i@, so that all the intervals are 'within' @i@. If there are no gaps or if the
-- input is empty, then 'Nothing' is returned.
--
-- >>> gapsWithin (iv 9 1) [iv 5 0, iv 2 7, iv 3 12]
-- Just [(5, 7),(9, 10)]
gapsWithin :: ( Applicative f
, Witherable f
, Monoid (f (Interval a))
, Monoid (f (Maybe (Interval a)))
, IntervalSizeable a b
, IntervalCombinable i0 a
, IntervalCombinable i1 a
) =>
i0 a -- ^ i
-> f (i1 a) -- ^ x
-> Maybe (f (Interval a))
gapsWithin i x
| null x = Nothing
| null res = Nothing
| otherwise = Just res
where s = pure (endervalFromBegin 0 i)
e = pure (beginervalFromEnd 0 i)
ivs = mapMaybe (clip i) (filterNotDisjoint i x)
res = catMaybes $ gapsM ( s <> ivs <> e )
-- The Box is an internal type used to hold accumulated, combined intervals in
-- 'combineIntervalsL'.
newtype Box a = Box { unBox :: [a] }
packIntervalBoxes :: (Intervallic i a)=> [i a] -> [Box (Interval a)]
packIntervalBoxes = fmap (\z -> Box [getInterval z])
instance (Ord a) => Semigroup (Box (Interval a)) where
Box x <> Box y = Box $ listCombiner (<->) x y
-- | Returns a container of intervals where any intervals that meet or share support
-- are combined into one interval. *To work properly, the input should
-- be sorted*. See 'combineIntervalsL' for a version that works only on lists.
--
-- >>> combineIntervals [iv 10 0, iv 5 2, iv 2 10, iv 2 13]
-- [(0, 12),(13, 15)]
combineIntervals :: ( Applicative f
, Ord a
, Intervallic i a
, Monoid (f (Interval a))
, Foldable f ) =>
f (i a) ->
f (Interval a)
combineIntervals x =
foldl' (\x y -> x <> pure y) mempty (combineIntervalsL $ toList x)
-- TODO: surely combineIntervals and combineIntervalsL could be combined
-- | Returns a list of intervals where any intervals that meet or share support
-- are combined into one interval. *To work properly, the input list should
-- be sorted*.
--
-- >>> combineIntervalsL [iv 10 0, iv 5 2, iv 2 10, iv 2 13]
-- [(0, 12),(13, 15)]
combineIntervalsL :: (Intervallic i a)=> [i a] -> [Interval a]
combineIntervalsL l = unBox $ foldl' (<>) (Box []) (packIntervalBoxes l)
-- Internal function for combining maybe intervals in the 'combineIntervalsL'
-- function
(<->) :: (IntervalCombinable i a) =>
Maybe (i a)
-> Maybe (i a)
-> [Interval a]
(<->) Nothing Nothing = []
(<->) Nothing (Just y) = [getInterval y]
(<->) (Just x) Nothing = [getInterval x]
(<->) (Just x) (Just y) = (<+>) (getInterval x) (getInterval y)
-- | Given a predicate combinator, a predicate, and list of intervals, returns
-- the input unchanged if the predicate combinator is @True@. Otherwise, returns
-- an empty list. See 'nothingIfAny' and 'nothingIfNone' for examples.
nothingIf :: (Monoid (f (i a)), Filterable f)=>
((i a -> Bool) -> f (i a) -> Bool) -- ^ e.g. 'any' or 'all'
-> (i a -> Bool) -- ^ predicate to apply to each element of input list
-> f (i a)
-> Maybe (f (i a))
nothingIf quantifier predicate x = if quantifier predicate x then Nothing else Just x
-- | Returns the 'Nothing' if *none* of the element of input satisfy
-- the predicate condition.
--
-- For example, the following returns 'Nothing' because none of the intervals
-- in the input list 'starts' (3, 5).
--
-- >>> nothingIfNone (starts (iv 2 3)) [iv 1 3, iv 1 5]
-- Nothing
--
-- In the following, (3, 5) 'starts' (3, 6), so 'Just' the input is returned.
--
-- >>> nothingIfNone (starts (iv 2 3)) [iv 3 3, iv 1 5]
-- Just [(3, 6),(5, 6)]
--
nothingIfNone :: (Monoid (f (i a)), Foldable f, Filterable f)=>
(i a -> Bool) -- ^ predicate to apply to each element of input list
-> f (i a)
-> Maybe (f (i a))
nothingIfNone = nothingIf (\f x -> (not.any f) x)
-- | Returns 'Nothing' if *any* of the element of input satisfy the predicate condition.
--
-- >>> nothingIfAny (starts (iv 2 3)) [iv 3 3, iv 1 5]
-- Just [(3, 6),(5, 6)]
--
-- >>> nothingIfAny (starts (iv 2 3)) [iv 3 3, iv 1 5]
-- Nothing
nothingIfAny :: (Monoid (f (i a)), Foldable f, Filterable f)=>
(i a -> Bool) -- ^ predicate to apply to each element of input list
-> f (i a)
-> Maybe (f (i a))
nothingIfAny = nothingIf any
-- | Returns 'Nothing' if *all* of the element of input satisfy the predicate condition.
-- >>> nothingIfAll (starts (iv 2 3)) [iv 3 3, iv 4 3]
-- Nothing
nothingIfAll :: (Monoid (f (i a)), Foldable f, Filterable f)=>
(i a -> Bool) -- ^ predicate to apply to each element of input list
-> f (i a)
-> Maybe (f (i a))
nothingIfAll = nothingIf all
-- | Creates a function for filtering a 'Witherable.Filterable' of @i1 a@s
-- by comparing the @Interval a@s that of an @i0 a@.
makeFilter :: ( Filterable f
, Intervallic i0 a
, Intervallic i1 a) =>
ComparativePredicateOf2 (i0 a) (i1 a)
-> i0 a
-> (f (i1 a) -> f (i1 a))
makeFilter f p = Witherable.filter (f p)
{- |
Filter 'Witherable.Filterable' containers of one @'Intervallic'@ type based by comparing to
a (potentially different) 'Intervallic' type using the corresponding interval
predicate function.
-}
filterOverlaps, filterOverlappedBy, filterBefore, filterAfter,
filterStarts, filterStartedBy, filterFinishes, filterFinishedBy,
filterMeets, filterMetBy, filterDuring, filterContains, filterEquals,
filterDisjoint, filterNotDisjoint, filterConcur, filterWithin,
filterEnclose, filterEnclosedBy ::
( Filterable f , Intervallic i0 a, Intervallic i1 a) =>
i0 a -> f (i1 a) -> f (i1 a)
filterOverlaps = makeFilter overlaps
filterOverlappedBy = makeFilter overlappedBy
filterBefore = makeFilter before
filterAfter = makeFilter after
filterStarts = makeFilter starts
filterStartedBy = makeFilter startedBy
filterFinishes = makeFilter finishes
filterFinishedBy = makeFilter finishedBy
filterMeets = makeFilter meets
filterMetBy = makeFilter metBy
filterDuring = makeFilter during
filterContains = makeFilter contains
filterEquals = makeFilter equals
filterDisjoint = makeFilter disjoint
filterNotDisjoint = makeFilter notDisjoint
filterConcur = makeFilter concur
filterWithin = makeFilter within
filterEnclose = makeFilter enclose
filterEnclosedBy = makeFilter enclosedBy
-- | Folds over a list of Paired Intervals and in the case that the 'getPairData'
-- is equal between two sequential meeting intervals, these two intervals are
-- combined into one. This function is "safe" in the sense that if the input is
-- invalid and contains any sequential pairs of intervals with an @IntervalRelation@,
-- other than 'Meets', then the function returns an empty list.
foldMeetingSafe :: (Eq b, Ord a, Show a) =>
[ PairedInterval b a ] -- ^ Be sure this only contains intervals
-- that sequentially 'meets'.
-> [ PairedInterval b a ]
foldMeetingSafe l = maybe [] (getMeeting . foldMeeting) (parseMeeting l)
-- | Folds over a list of Meeting Paired Intervals and in the case that the 'getPairData'
-- is equal between two sequential meeting intervals, these two intervals are
-- combined into one.
foldMeeting :: (Eq b, Ord a, Show a) =>
Meeting [PairedInterval b a ]
-> Meeting [PairedInterval b a ]
foldMeeting (Meeting l) = foldl' joinMeetingPairedInterval (Meeting []) (packMeeting l)
-- This type identifies that @a@ contains intervals that sequentially meet one
-- another.
newtype Meeting a = Meeting { getMeeting :: a } deriving (Eq, Show)
-- Box up Meeting.
packMeeting :: [a] -> [Meeting [a]]
packMeeting = fmap (\z -> Meeting [z])
-- Test a list of intervals to be sure they all meet; if not return Nothing.
parseMeeting :: Intervallic i a => [i a] -> Maybe (Meeting [i a])
parseMeeting x
| all ( == Meets ) (relationsL x) = Just $ Meeting x
| otherwise = Nothing
-- A specific case of 'joinMeeting' for @PairedIntervals@.
joinMeetingPairedInterval :: (Eq b, Ord a, Show a) =>
Meeting [PairedInterval b a]
-> Meeting [PairedInterval b a]
-> Meeting [PairedInterval b a]
joinMeetingPairedInterval = joinMeeting equalPairData
-- A general function for combining any two @Meeting [i a]@ by 'listCombiner'.
joinMeeting :: Intervallic i a =>
ComparativePredicateOf1 (i a)
-> Meeting [ i a ]
-> Meeting [ i a ]
-> Meeting [ i a ]
joinMeeting f (Meeting x) (Meeting y) = Meeting $ listCombiner (join2MeetingWhen f) x y
-- The intervals @x@ and @y@ should meet! The predicate function @p@ determines
-- when the two intervals that meet should be combined.
join2MeetingWhen :: Intervallic i a =>
ComparativePredicateOf1 (i a)
-> Maybe (i a)
-> Maybe (i a)
-> [i a]
join2MeetingWhen p Nothing Nothing = []
join2MeetingWhen p Nothing (Just y) = [y]
join2MeetingWhen p (Just x) Nothing = [x]
join2MeetingWhen p (Just x) (Just y)
| p x y = [ setInterval y (extenterval x y) ]
| otherwise = pure x <> pure y
{- |
Takes two *ordered* events, x <= y, and "disjoins" them in the case that the
two events have different states, creating a sequence (list) of new events that
sequentially meet one another. Since x <= y, there are 7 possible interval
relations between x and y. If the states of x and y are equal and x is not
before y, then x and y are combined into a single event.
-}
disjoinPaired :: ( Eq b
, Monoid b
, Show a
, IntervalSizeable a c) =>
(PairedInterval b) a
-> (PairedInterval b) a
-> Meeting [(PairedInterval b) a]
disjoinPaired o e = case relate x y of
Before -> Meeting [ x, evp e1 b2 mempty, y ]
Meets -> foldMeeting $ Meeting [ x, y ]
Overlaps -> foldMeeting $ Meeting [ evp b1 b2 s1, evp b2 e1 sc, evp e1 e2 s2 ]
FinishedBy -> foldMeeting $ Meeting [ evp b1 b2 s1, ev i2 sc ]
Contains -> foldMeeting $ Meeting [ evp b1 b2 s1, evp b2 e2 sc, evp e2 e1 s1 ]
Starts -> foldMeeting $ Meeting [ ev i1 sc, evp e1 e2 s2 ]
_ -> Meeting [ ev i1 sc ] {- Equals case -}
where x = min o e
y = max o e
i1 = getInterval x
i2 = getInterval y
s1 = getPairData x
s2 = getPairData y
sc = s1 <> s2
b1 = begin x
b2 = begin y
e1 = end x
e2 = end y
ev = flip makePairedInterval
evp = \b e s -> ev (beginerval (diff e b) b) s
{- |
The internal function for converting a non-disjoint, ordered sequence of
events into a disjoint, ordered sequence of events. The function operates
by recursion on a pair of events and the input events. The first of the
is the accumulator set -- the disjoint events that need no longer be
compared to input events. The second of the pair are disjoint events that
still need to be compared to be input events.
-}
recurseDisjoin :: ( Monoid b, Eq b, IntervalSizeable a c, Show a ) =>
([(PairedInterval b) a ], [(PairedInterval b) a ])
-> [(PairedInterval b) a ]
-> [(PairedInterval b) a ]
recurseDisjoin (acc, o:os) [] = acc <> (o:os) -- the "final" pattern
recurseDisjoin (acc, []) [] = acc -- another "final" pattern
recurseDisjoin (acc, []) (e:es) = recurseDisjoin (acc, [e]) es -- the "initialize" pattern
recurseDisjoin (acc, o:os) (e:es) -- the "operating" patterns
-- If input event is equal to the first comparator, skip the comparison.
| e == o = recurseDisjoin (acc, o:os) es
{- If o is either before or meets e, then
the first of the combined events can be put into the accumulator.
That is, since the inputs events are ordered, once the beginning of o
is before or meets e, then we are assured that all periods up to the
beginning of o are fully disjoint and subsequent input events will
not overlap these in any way. -}
| (before <|> meets) o e = recurseDisjoin (acc <> nh, recurseDisjoin ([], nt) os ) es
--The standard recursive operation.
| otherwise = recurseDisjoin (acc, recurseDisjoin ([], n) os ) es
where n = getMeeting $ disjoinPaired o e
nh = maybeToList (headMay n)
nt = tailSafe n
{- |
Convert an ordered sequence of @PairedInterval b a@. that may have any interval relation
('before', 'starts', etc) into a sequence of sequentially meeting @PairedInterval b a@.
That is, a sequence where one the end of one interval meets the beginning of
the subsequent event. The 'getPairData' of the input @PairedIntervals@ are
combined using the Monoid '<>' function, hence the pair data must be a
'Monoid' instance.
-}
formMeetingSequence :: ( Eq b
, Show a
, Monoid b
, IntervalSizeable a c) =>
[ PairedInterval b a ]
-> [ PairedInterval b a ]
formMeetingSequence x
| null x = []
| allMeet x && not (hasEqData x) = x
| otherwise = formMeetingSequence (recurseDisjoin ([], []) x)
-- recurseDisjoin ([], []) (recurseDisjoin ([], []) (recurseDisjoin ([], []) x))
-- the multiple passes of recurseDisjoin is to handle the situation where the
-- initial passes almost disjoins all the events correctly into a meeting sequence
-- but due to nesting of intervals in the input -- some of the sequential pairs have
-- the same data after the first pass. The recursive passes merges any sequential
-- intervals that have the same data.
--
-- There is probably a more efficient way to do this
allMeet :: (Ord a) => [PairedInterval b a] -> Bool
allMeet x = all ( == Meets) ( relationsL x )
hasEqData :: (Eq b) => [PairedInterval b a] -> Bool
hasEqData x = or (L.fold (makeFolder (==)) (fmap getPairData x) :: [Bool])