    -- | Maps containing non-overlapping intervals.

    module Agda.Utils.RangeMap
      ( IsBasicRangeMap(..)
      , several
      , PairInt(..)
      , RangeMap(..)
      , rangeMapInvariant
      , fromNonOverlappingNonEmptyAscendingList
      , insert
      , splitAt
      , insideAndOutside
      , restrictTo
      )
      where

    import Prelude hiding (null, splitAt)

    import Control.DeepSeq

    import Data.IntMap (IntMap)
    import qualified Data.IntMap as IntMap

    import Data.Map.Strict (Map)
    import qualified Data.Map.Strict as Map

    import Data.Semigroup

    import Data.Strict.Tuple (Pair(..))

    import Agda.Interaction.Highlighting.Range
    import Agda.Utils.List
    import Agda.Utils.Null

    ------------------------------------------------------------------------
    -- An abstraction

    -- | A class that is intended to make it easy to swap between
    -- different range map implementations.
    --
    -- Note that some 'RangeMap' operations are not included in this
    -- class.

    class IsBasicRangeMap a m | m -> a where

      -- | The map @'singleton' rs x@ contains the ranges from @rs@, and
      -- every position in those ranges is associated with @x@.

      singleton :: Ranges -> a -> m

      -- | Converts range maps to 'IntMap's from positions to values.

      toMap :: m -> IntMap a

      -- | Converts the map to a list. The ranges are non-overlapping and
      -- non-empty, and earlier ranges precede later ones in the list.

      toList :: m -> [(Range, a)]

      -- | Returns the smallest range covering everything in the map (or
      -- 'Nothing', if the range would be empty).
      --
      -- Note that the default implementation of this operation might be
      -- inefficient.

      coveringRange :: m -> Maybe Range
      coveringRange m
    f = do
        min <- (Int, a) -> Int
    forall a b. (a, b) -> a
    fst ((Int, a) -> Int) -> Maybe (Int, a) -> Maybe Int
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> IntMap a -> Maybe (Int, a)
    forall a. IntMap a -> Maybe (Int, a)
    IntMap.lookupMin IntMap a
    m
        max <- fst <$> IntMap.lookupMax m
        return (Range { from = min, to = max + 1 })
        where
        m :: IntMap a
    m = m -> IntMap a
    forall a m. IsBasicRangeMap a m => m -> IntMap a
    toMap m
    f

    -- | Like 'singleton', but with several 'Ranges' instead of only one.

    several ::
      (IsBasicRangeMap a hl, Monoid hl) =>
      [Ranges] -> a -> hl
    several :: forall a hl.
    (IsBasicRangeMap a hl, Monoid hl) =>
    [Ranges] -> a -> hl
    several [Ranges]
    rss a
    m = [hl] -> hl
    forall a. Monoid a => [a] -> a
    mconcat ([hl] -> hl) -> [hl] -> hl
    forall a b. (a -> b) -> a -> b
    $ (Ranges -> hl) -> [Ranges] -> [hl]
    forall a b. (a -> b) -> [a] -> [b]
    map ((Ranges -> a -> hl) -> a -> Ranges -> hl
    forall a b c. (a -> b -> c) -> b -> a -> c
    flip Ranges -> a -> hl
    forall a m. IsBasicRangeMap a m => Ranges -> a -> m
    singleton a
    m) [Ranges]
    rss

    ------------------------------------------------------------------------
    -- A strict pair type

    -- | A strict pair type where the first argument must be an 'Int'.
    --
    -- This type is included because there is no 'NFData' instance for
    -- 'Pair' in the package @strict@ before version 4.

    newtype PairInt a = PairInt (Pair Int a)
      deriving Int -> PairInt a -> ShowS
    [PairInt a] -> ShowS
    PairInt a -> String
    (Int -> PairInt a -> ShowS)
    -> (PairInt a -> String)
    -> ([PairInt a] -> ShowS)
    -> Show (PairInt a)
    forall a. Show a => Int -> PairInt a -> ShowS
    forall a. Show a => [PairInt a] -> ShowS
    forall a. Show a => PairInt a -> String
    forall a.
    (Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
    $cshowsPrec :: forall a. Show a => Int -> PairInt a -> ShowS
    showsPrec :: Int -> PairInt a -> ShowS
    $cshow :: forall a. Show a => PairInt a -> String
    show :: PairInt a -> String
    $cshowList :: forall a. Show a => [PairInt a] -> ShowS
    showList :: [PairInt a] -> ShowS
    Show

    instance NFData a => NFData (PairInt a) where
      rnf :: PairInt a -> ()
    rnf (PairInt (Int
    _ :!: a
    y)) = a -> ()
    forall a. NFData a => a -> ()
    rnf a
    y

    -- | Constructs a pair.

    pair :: Int -> a -> PairInt a
    pair :: forall a. Int -> a -> PairInt a
    pair Int
    x a
    y = Pair Int a -> PairInt a
    forall a. Pair Int a -> PairInt a
    PairInt (Int
    x Int -> a -> Pair Int a
    forall a b. a -> b -> Pair a b
    :!: a
    y)

    ------------------------------------------------------------------------
    -- The type

    -- | Maps containing non-overlapping intervals.
    --
    -- The implementation does not use IntMap, because IntMap does not
    -- come with a constant-time size function.
    --
    -- Note the invariant which 'RangeMap's should satisfy
    -- ('rangeMapInvariant').

    newtype RangeMap a = RangeMap
      { forall a. RangeMap a -> Map Int (PairInt a)
    rangeMap :: Map Int (PairInt a)
        -- ^ The keys are starting points of ranges, and the pairs contain
        -- endpoints and values.
      }
      deriving (Int -> RangeMap a -> ShowS
    [RangeMap a] -> ShowS
    RangeMap a -> String
    (Int -> RangeMap a -> ShowS)
    -> (RangeMap a -> String)
    -> ([RangeMap a] -> ShowS)
    -> Show (RangeMap a)
    forall a. Show a => Int -> RangeMap a -> ShowS
    forall a. Show a => [RangeMap a] -> ShowS
    forall a. Show a => RangeMap a -> String
    forall a.
    (Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
    $cshowsPrec :: forall a. Show a => Int -> RangeMap a -> ShowS
    showsPrec :: Int -> RangeMap a -> ShowS
    $cshow :: forall a. Show a => RangeMap a -> String
    show :: RangeMap a -> String
    $cshowList :: forall a. Show a => [RangeMap a] -> ShowS
    showList :: [RangeMap a] -> ShowS
    Show, RangeMap a -> ()
    (RangeMap a -> ()) -> NFData (RangeMap a)
    forall a. NFData a => RangeMap a -> ()
    forall a. (a -> ()) -> NFData a
    $crnf :: forall a. NFData a => RangeMap a -> ()
    rnf :: RangeMap a -> ()
    NFData)

    -- | Invariant for 'RangeMap'.
    --
    -- The ranges must not be empty, and they must not overlap.

    rangeMapInvariant :: RangeMap a -> Bool
    rangeMapInvariant :: forall a. RangeMap a -> Bool
    rangeMapInvariant RangeMap a
    f = [Bool] -> Bool
    forall (t :: * -> *). Foldable t => t Bool -> Bool
    and
      [ (Range -> Bool) -> [Range] -> Bool
    forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
    all Range -> Bool
    rangeInvariant [Range]
    rs
      , (Range -> Bool) -> [Range] -> Bool
    forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
    all (Bool -> Bool
    not (Bool -> Bool) -> (Range -> Bool) -> Range -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Range -> Bool
    forall a. Null a => a -> Bool
    null) [Range]
    rs
      , [Range] -> Bool -> (Range -> [Range] -> Bool) -> Bool
    forall a b. [a] -> b -> (a -> [a] -> b) -> b
    caseList [Range]
    rs Bool
    True ((Range -> [Range] -> Bool) -> Bool)
    -> (Range -> [Range] -> Bool) -> Bool
    forall a b. (a -> b) -> a -> b
    $ \ Range
    r [Range]
    rs' ->
          [Bool] -> Bool
    forall (t :: * -> *). Foldable t => t Bool -> Bool
    and ([Bool] -> Bool) -> [Bool] -> Bool
    forall a b. (a -> b) -> a -> b
    $ (Int -> Int -> Bool) -> [Int] -> [Int] -> [Bool]
    forall a b c. (a -> b -> c) -> [a] -> [b] -> [c]
    zipWith Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    (<=) ((Range -> Int) -> [Range] -> [Int]
    forall a b. (a -> b) -> [a] -> [b]
    map Range -> Int
    to ([Range] -> [Int]) -> [Range] -> [Int]
    forall a b. (a -> b) -> a -> b
    $ Range -> [Range] -> [Range]
    forall a. a -> [a] -> [a]
    init1 Range
    r [Range]
    rs') ((Range -> Int) -> [Range] -> [Int]
    forall a b. (a -> b) -> [a] -> [b]
    map Range -> Int
    from [Range]
    rs')
      ]
      where
      rs :: [Range]
    rs = ((Range, a) -> Range) -> [(Range, a)] -> [Range]
    forall a b. (a -> b) -> [a] -> [b]
    map (Range, a) -> Range
    forall a b. (a, b) -> a
    fst ([(Range, a)] -> [Range]) -> [(Range, a)] -> [Range]
    forall a b. (a -> b) -> a -> b
    $ RangeMap a -> [(Range, a)]
    forall a m. IsBasicRangeMap a m => m -> [(Range, a)]
    toList RangeMap a
    f

    ------------------------------------------------------------------------
    -- Construction, conversion and inspection

    instance Null (RangeMap a) where
      empty :: RangeMap a
    empty = RangeMap { rangeMap :: Map Int (PairInt a)
    rangeMap = Map Int (PairInt a)
    forall k a. Map k a
    Map.empty }
      null :: RangeMap a -> Bool
    null  = Map Int (PairInt a) -> Bool
    forall k a. Map k a -> Bool
    Map.null (Map Int (PairInt a) -> Bool)
    -> (RangeMap a -> Map Int (PairInt a)) -> RangeMap a -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . RangeMap a -> Map Int (PairInt a)
    forall a. RangeMap a -> Map Int (PairInt a)
    rangeMap

    instance IsBasicRangeMap a (RangeMap a) where
      singleton :: Ranges -> a -> RangeMap a
    singleton (Ranges [Range]
    rs) a
    m =
        RangeMap { rangeMap :: Map Int (PairInt a)
    rangeMap = [(Int, PairInt a)] -> Map Int (PairInt a)
    forall k a. [(k, a)] -> Map k a
    Map.fromDistinctAscList [(Int, PairInt a)]
    rms }
        where
        rms :: [(Int, PairInt a)]
    rms =
          [ (Range -> Int
    from Range
    r, Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair (Range -> Int
    to Range
    r) a
    m)
          | Range
    r <- [Range]
    rs
          , Bool -> Bool
    not (Range -> Bool
    forall a. Null a => a -> Bool
    null Range
    r)
          ]

      toMap :: RangeMap a -> IntMap a
    toMap RangeMap a
    f =
        [(Int, a)] -> IntMap a
    forall a. [(Int, a)] -> IntMap a
    IntMap.fromList
          [ (Int
    p, a
    m)
          | (Range
    r, a
    m) <- RangeMap a -> [(Range, a)]
    forall a m. IsBasicRangeMap a m => m -> [(Range, a)]
    toList RangeMap a
    f
          , Int
    p <- Range -> [Int]
    rangeToPositions Range
    r
          ]

      toList :: RangeMap a -> [(Range, a)]
    toList =
        ((Int, PairInt a) -> (Range, a))
    -> [(Int, PairInt a)] -> [(Range, a)]
    forall a b. (a -> b) -> [a] -> [b]
    map (\(Int
    f, PairInt (Int
    t :!: a
    a)) -> (Range { from :: Int
    from = Int
    f, to :: Int
    to = Int
    t } , a
    a)) ([(Int, PairInt a)] -> [(Range, a)])
    -> (RangeMap a -> [(Int, PairInt a)]) -> RangeMap a -> [(Range, a)]
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    .
        Map Int (PairInt a) -> [(Int, PairInt a)]
    forall k a. Map k a -> [(k, a)]
    Map.toAscList (Map Int (PairInt a) -> [(Int, PairInt a)])
    -> (RangeMap a -> Map Int (PairInt a))
    -> RangeMap a
    -> [(Int, PairInt a)]
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    .
        RangeMap a -> Map Int (PairInt a)
    forall a. RangeMap a -> Map Int (PairInt a)
    rangeMap

      coveringRange :: RangeMap a -> Maybe Range
    coveringRange RangeMap a
    f = do
        min <- (Int, PairInt a) -> Int
    forall a b. (a, b) -> a
    fst ((Int, PairInt a) -> Int) -> Maybe (Int, PairInt a) -> Maybe Int
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> Map Int (PairInt a) -> Maybe (Int, PairInt a)
    forall k a. Map k a -> Maybe (k, a)
    Map.lookupMin (RangeMap a -> Map Int (PairInt a)
    forall a. RangeMap a -> Map Int (PairInt a)
    rangeMap RangeMap a
    f)
        max <- (\(Int
    _, PairInt (Int
    p :!: a
    _)) -> Int
    p) <$> Map.lookupMax (rangeMap f)
        return (Range { from = min, to = max })

    -- | Converts a list of pairs of ranges and values to a 'RangeMap'.
    -- The ranges have to be non-overlapping and non-empty, and earlier
    -- ranges have to precede later ones.

    fromNonOverlappingNonEmptyAscendingList :: [(Range, a)] -> RangeMap a
    fromNonOverlappingNonEmptyAscendingList :: forall a. [(Range, a)] -> RangeMap a
    fromNonOverlappingNonEmptyAscendingList =
      Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Map Int (PairInt a) -> RangeMap a)
    -> ([(Range, a)] -> Map Int (PairInt a))
    -> [(Range, a)]
    -> RangeMap a
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    .
      [(Int, PairInt a)] -> Map Int (PairInt a)
    forall k a. [(k, a)] -> Map k a
    Map.fromDistinctAscList ([(Int, PairInt a)] -> Map Int (PairInt a))
    -> ([(Range, a)] -> [(Int, PairInt a)])
    -> [(Range, a)]
    -> Map Int (PairInt a)
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    .
      ((Range, a) -> (Int, PairInt a))
    -> [(Range, a)] -> [(Int, PairInt a)]
    forall a b. (a -> b) -> [a] -> [b]
    map (\(Range
    r, a
    m) -> (Range -> Int
    from Range
    r, Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair (Range -> Int
    to Range
    r) a
    m))

    -- | The number of ranges in the map.
    --
    -- This function should not be exported.

    size :: RangeMap a -> Int
    size :: forall a. RangeMap a -> Int
    size = Map Int (PairInt a) -> Int
    forall k a. Map k a -> Int
    Map.size (Map Int (PairInt a) -> Int)
    -> (RangeMap a -> Map Int (PairInt a)) -> RangeMap a -> Int
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . RangeMap a -> Map Int (PairInt a)
    forall a. RangeMap a -> Map Int (PairInt a)
    rangeMap

    ------------------------------------------------------------------------
    -- Merging

    -- | Inserts a value, along with a corresponding 'Range', into a
    -- 'RangeMap'. No attempt is made to merge adjacent ranges with equal
    -- values.
    --
    -- The function argument is used to combine values. The inserted value
    -- is given as the first argument to the function.

    insert :: (a -> a -> a) -> Range -> a -> RangeMap a -> RangeMap a
    insert :: forall a. (a -> a -> a) -> Range -> a -> RangeMap a -> RangeMap a
    insert a -> a -> a
    combine Range
    r a
    m (RangeMap Map Int (PairInt a)
    f)
      | Range -> Bool
    forall a. Null a => a -> Bool
    null Range
    r    = Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap Map Int (PairInt a)
    f
      | Bool
    otherwise =
        case Maybe (PairInt a)
    equal of
          Just (PairInt (Int
    p :!: a
    m')) ->
            case Int -> Int -> Ordering
    forall a. Ord a => a -> a -> Ordering
    compare (Range -> Int
    to Range
    r) Int
    p of
              Ordering
    EQ ->
                -- The range r matches exactly.
                Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Map Int (PairInt a) -> RangeMap a)
    -> Map Int (PairInt a) -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
                Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert (Range -> Int
    from Range
    r) (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair Int
    p (a -> a -> a
    combine a
    m a
    m')) Map Int (PairInt a)
    f
              Ordering
    LT ->
                -- The range r is strictly shorter.
                Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Map Int (PairInt a) -> RangeMap a)
    -> Map Int (PairInt a) -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
                Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert (Range -> Int
    to Range
    r) (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair Int
    p a
    m') (Map Int (PairInt a) -> Map Int (PairInt a))
    -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall a b. (a -> b) -> a -> b
    $
                Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert (Range -> Int
    from Range
    r) (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair (Range -> Int
    to Range
    r) (a -> a -> a
    combine a
    m a
    m')) Map Int (PairInt a)
    f
              Ordering
    GT ->
                -- The range r is strictly longer. Continue recursively.
                (a -> a -> a) -> Range -> a -> RangeMap a -> RangeMap a
    forall a. (a -> a -> a) -> Range -> a -> RangeMap a -> RangeMap a
    insert a -> a -> a
    combine (Range { from :: Int
    from = Int
    p, to :: Int
    to = Range -> Int
    to Range
    r }) a
    m (RangeMap a -> RangeMap a) -> RangeMap a -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
                Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Map Int (PairInt a) -> RangeMap a)
    -> Map Int (PairInt a) -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
                Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert (Range -> Int
    from Range
    r) (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair Int
    p (a -> a -> a
    combine a
    m a
    m')) Map Int (PairInt a)
    f
          Maybe (PairInt a)
    Nothing ->
            -- Find the part of r that does not overlap with anything in
            -- smaller or larger, if any.
            case (Maybe (Int, PairInt a)
    overlapLeft, Maybe Int
    overlapRight) of
              (Maybe (Int, PairInt a)
    Nothing, Maybe Int
    Nothing) ->
                -- No overlap.
                Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Map Int (PairInt a) -> RangeMap a)
    -> Map Int (PairInt a) -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
                Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert (Range -> Int
    from Range
    r) (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair (Range -> Int
    to Range
    r) a
    m) Map Int (PairInt a)
    f
              (Maybe (Int, PairInt a)
    Nothing, Just Int
    p) ->
                -- Overlap on the right. Continue recursively.
                (a -> a -> a) -> Range -> a -> RangeMap a -> RangeMap a
    forall a. (a -> a -> a) -> Range -> a -> RangeMap a -> RangeMap a
    insert a -> a -> a
    combine (Range { from :: Int
    from = Int
    p, to :: Int
    to = Range -> Int
    to Range
    r }) a
    m (RangeMap a -> RangeMap a) -> RangeMap a -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
                Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Map Int (PairInt a) -> RangeMap a)
    -> Map Int (PairInt a) -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
                Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert (Range -> Int
    from Range
    r) (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair Int
    p a
    m) Map Int (PairInt a)
    f
              (Just (Int
    p1, PairInt (Int
    p2 :!: a
    m')), Just Int
    p3) ->
                -- Overlap on both sides. Continue recursively.
                (a -> a -> a) -> Range -> a -> RangeMap a -> RangeMap a
    forall a. (a -> a -> a) -> Range -> a -> RangeMap a -> RangeMap a
    insert a -> a -> a
    combine (Range { from :: Int
    from = Int
    p3, to :: Int
    to = Range -> Int
    to Range
    r }) a
    m (RangeMap a -> RangeMap a) -> RangeMap a -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
                Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Map Int (PairInt a) -> RangeMap a)
    -> Map Int (PairInt a) -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
                (if Int
    p2 Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Int
    p3 then
                   -- The left range ends exactly where the right range
                   -- starts.
                   Map Int (PairInt a) -> Map Int (PairInt a)
    forall a. a -> a
    id
                 else
                   -- There is something between the left and right
                   -- ranges.
                   Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert Int
    p2 (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair Int
    p3 a
    m)) (Map Int (PairInt a) -> Map Int (PairInt a))
    -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall a b. (a -> b) -> a -> b
    $
                Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert (Range -> Int
    from Range
    r) (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair Int
    p2 (a -> a -> a
    combine a
    m a
    m')) (Map Int (PairInt a) -> Map Int (PairInt a))
    -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall a b. (a -> b) -> a -> b
    $
                Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert Int
    p1 (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair (Range -> Int
    from Range
    r) a
    m') Map Int (PairInt a)
    f
              (Just (Int
    p1, PairInt (Int
    p2 :!: a
    m')), Maybe Int
    Nothing) ->
                case Int -> Int -> Ordering
    forall a. Ord a => a -> a -> Ordering
    compare Int
    p2 (Range -> Int
    to Range
    r) of
                  Ordering
    LT ->
                    -- Overlap on the left, the left range ends before r.
                    Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Map Int (PairInt a) -> RangeMap a)
    -> Map Int (PairInt a) -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
                    Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert Int
    p2 (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair (Range -> Int
    to Range
    r) a
    m) (Map Int (PairInt a) -> Map Int (PairInt a))
    -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall a b. (a -> b) -> a -> b
    $
                    Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert (Range -> Int
    from Range
    r) (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair Int
    p2 (a -> a -> a
    combine a
    m a
    m')) (Map Int (PairInt a) -> Map Int (PairInt a))
    -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall a b. (a -> b) -> a -> b
    $
                    Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert Int
    p1 (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair (Range -> Int
    from Range
    r) a
    m') Map Int (PairInt a)
    f
                  Ordering
    EQ ->
                    -- Overlap on the left, the left range ends where r
                    -- ends.
                    Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Map Int (PairInt a) -> RangeMap a)
    -> Map Int (PairInt a) -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
                    Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert (Range -> Int
    from Range
    r) (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair (Range -> Int
    to Range
    r) (a -> a -> a
    combine a
    m a
    m')) (Map Int (PairInt a) -> Map Int (PairInt a))
    -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall a b. (a -> b) -> a -> b
    $
                    Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert Int
    p1 (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair (Range -> Int
    from Range
    r) a
    m') Map Int (PairInt a)
    f
                  Ordering
    GT ->
                    -- Overlap on the left, the left range ends after r.
                    Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Map Int (PairInt a) -> RangeMap a)
    -> Map Int (PairInt a) -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
                    Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert (Range -> Int
    to Range
    r) (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair Int
    p2 a
    m') (Map Int (PairInt a) -> Map Int (PairInt a))
    -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall a b. (a -> b) -> a -> b
    $
                    Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert (Range -> Int
    from Range
    r) (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair (Range -> Int
    to Range
    r) (a -> a -> a
    combine a
    m a
    m')) (Map Int (PairInt a) -> Map Int (PairInt a))
    -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall a b. (a -> b) -> a -> b
    $
                    Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert Int
    p1 (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair (Range -> Int
    from Range
    r) a
    m') Map Int (PairInt a)
    f
        where
        (Map Int (PairInt a)
    smaller, Maybe (PairInt a)
    equal, Map Int (PairInt a)
    larger) = Int
    -> Map Int (PairInt a)
    -> (Map Int (PairInt a), Maybe (PairInt a), Map Int (PairInt a))
    forall k a. Ord k => k -> Map k a -> (Map k a, Maybe a, Map k a)
    Map.splitLookup (Range -> Int
    from Range
    r) Map Int (PairInt a)
    f

        overlapRight :: Maybe Int
    overlapRight = case Map Int (PairInt a) -> Maybe (Int, PairInt a)
    forall k a. Map k a -> Maybe (k, a)
    Map.lookupMin Map Int (PairInt a)
    larger of
          Maybe (Int, PairInt a)
    Nothing -> Maybe Int
    forall a. Maybe a
    Nothing
          Just (Int
    from, PairInt a
    _)
            | Int
    from Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    < Range -> Int
    to Range
    r -> Int -> Maybe Int
    forall a. a -> Maybe a
    Just Int
    from
            | Bool
    otherwise   -> Maybe Int
    forall a. Maybe a
    Nothing

        overlapLeft :: Maybe (Int, PairInt a)
    overlapLeft = case Map Int (PairInt a) -> Maybe (Int, PairInt a)
    forall k a. Map k a -> Maybe (k, a)
    Map.lookupMax Map Int (PairInt a)
    smaller of
          Maybe (Int, PairInt a)
    Nothing -> Maybe (Int, PairInt a)
    forall a. Maybe a
    Nothing
          Just s :: (Int, PairInt a)
    s@(Int
    _, PairInt (Int
    to :!: a
    _))
            | Range -> Int
    from Range
    r Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    < Int
    to -> (Int, PairInt a) -> Maybe (Int, PairInt a)
    forall a. a -> Maybe a
    Just (Int, PairInt a)
    s
            | Bool
    otherwise   -> Maybe (Int, PairInt a)
    forall a. Maybe a
    Nothing

    -- | Merges 'RangeMap's by inserting every \"piece\" of the smaller
    -- one into the larger one.

    instance Semigroup a => Semigroup (RangeMap a) where
      RangeMap a
    f1 <> :: RangeMap a -> RangeMap a -> RangeMap a
    <> RangeMap a
    f2
        | RangeMap a -> Int
    forall a. RangeMap a -> Int
    size RangeMap a
    f1 Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    <= RangeMap a -> Int
    forall a. RangeMap a -> Int
    size RangeMap a
    f2 =
          ((Range, a) -> RangeMap a -> RangeMap a)
    -> RangeMap a -> [(Range, a)] -> RangeMap a
    forall a b. (a -> b -> b) -> b -> [a] -> b
    forall (t :: * -> *) a b.
    Foldable t =>
    (a -> b -> b) -> b -> t a -> b
    foldr ((Range -> a -> RangeMap a -> RangeMap a)
    -> (Range, a) -> RangeMap a -> RangeMap a
    forall a b c. (a -> b -> c) -> (a, b) -> c
    uncurry ((Range -> a -> RangeMap a -> RangeMap a)
     -> (Range, a) -> RangeMap a -> RangeMap a)
    -> (Range -> a -> RangeMap a -> RangeMap a)
    -> (Range, a)
    -> RangeMap a
    -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $ (a -> a -> a) -> Range -> a -> RangeMap a -> RangeMap a
    forall a. (a -> a -> a) -> Range -> a -> RangeMap a -> RangeMap a
    insert a -> a -> a
    forall a. Semigroup a => a -> a -> a
    (<>)) RangeMap a
    f2 (RangeMap a -> [(Range, a)]
    forall a m. IsBasicRangeMap a m => m -> [(Range, a)]
    toList RangeMap a
    f1)
        | Bool
    otherwise =
          ((Range, a) -> RangeMap a -> RangeMap a)
    -> RangeMap a -> [(Range, a)] -> RangeMap a
    forall a b. (a -> b -> b) -> b -> [a] -> b
    forall (t :: * -> *) a b.
    Foldable t =>
    (a -> b -> b) -> b -> t a -> b
    foldr ((Range -> a -> RangeMap a -> RangeMap a)
    -> (Range, a) -> RangeMap a -> RangeMap a
    forall a b c. (a -> b -> c) -> (a, b) -> c
    uncurry ((Range -> a -> RangeMap a -> RangeMap a)
     -> (Range, a) -> RangeMap a -> RangeMap a)
    -> (Range -> a -> RangeMap a -> RangeMap a)
    -> (Range, a)
    -> RangeMap a
    -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $ (a -> a -> a) -> Range -> a -> RangeMap a -> RangeMap a
    forall a. (a -> a -> a) -> Range -> a -> RangeMap a -> RangeMap a
    insert ((a -> a -> a) -> a -> a -> a
    forall a b c. (a -> b -> c) -> b -> a -> c
    flip a -> a -> a
    forall a. Semigroup a => a -> a -> a
    (<>))) RangeMap a
    f1 (RangeMap a -> [(Range, a)]
    forall a m. IsBasicRangeMap a m => m -> [(Range, a)]
    toList RangeMap a
    f2)

    -- | Merges 'RangeMap's by inserting every \"piece\" of the smaller
    -- one into the larger one.

    instance Semigroup a => Monoid (RangeMap a) where
      mempty :: RangeMap a
    mempty  = RangeMap a
    forall a. Null a => a
    empty
      mappend :: RangeMap a -> RangeMap a -> RangeMap a
    mappend = RangeMap a -> RangeMap a -> RangeMap a
    forall a. Semigroup a => a -> a -> a
    (<>)

    ------------------------------------------------------------------------
    -- Splitting

    -- | The value of @'splitAt' p f@ is a pair @(f1, f2)@ which contains
    -- everything from @f@. All the positions in @f1@ are less than @p@,
    -- and all the positions in @f2@ are greater than or equal to @p@.

    splitAt :: Int -> RangeMap a -> (RangeMap a, RangeMap a)
    splitAt :: forall a. Int -> RangeMap a -> (RangeMap a, RangeMap a)
    splitAt Int
    p RangeMap a
    f = (RangeMap a
    before, RangeMap a
    after)
      where
      (RangeMap a
    before, Maybe ((Int, PairInt a), (Int, PairInt a))
    _, RangeMap a
    after) = Int
    -> RangeMap a
    -> (RangeMap a, Maybe ((Int, PairInt a), (Int, PairInt a)),
        RangeMap a)
    forall a.
    Int
    -> RangeMap a
    -> (RangeMap a, Maybe ((Int, PairInt a), (Int, PairInt a)),
        RangeMap a)
    splitAt' Int
    p RangeMap a
    f

    -- | A variant of 'splitAt'. If a range in the middle was split into
    -- two pieces, then those two pieces are returned.

    splitAt' ::
      Int -> RangeMap a ->
      ( RangeMap a
      , Maybe ((Int, PairInt a), (Int, PairInt a))
      , RangeMap a
      )
    splitAt' :: forall a.
    Int
    -> RangeMap a
    -> (RangeMap a, Maybe ((Int, PairInt a), (Int, PairInt a)),
        RangeMap a)
    splitAt' Int
    p (RangeMap Map Int (PairInt a)
    f) =
      case Maybe (PairInt a)
    equal of
        Just PairInt a
    r  -> ( Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap Map Int (PairInt a)
    maybeOverlapping
                   , Maybe ((Int, PairInt a), (Int, PairInt a))
    forall a. Maybe a
    Nothing
                   , Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert Int
    p PairInt a
    r Map Int (PairInt a)
    larger)
                   )
        Maybe (PairInt a)
    Nothing ->
          -- Check if maybeOverlapping overlaps with p.
          case Map Int (PairInt a)
    -> Maybe ((Int, PairInt a), Map Int (PairInt a))
    forall k a. Map k a -> Maybe ((k, a), Map k a)
    Map.maxViewWithKey Map Int (PairInt a)
    maybeOverlapping of
            Maybe ((Int, PairInt a), Map Int (PairInt a))
    Nothing ->
              (RangeMap a
    forall a. Null a => a
    empty, Maybe ((Int, PairInt a), (Int, PairInt a))
    forall a. Maybe a
    Nothing, Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap Map Int (PairInt a)
    larger)
            Just ((Int
    from, PairInt (Int
    to :!: a
    m)), Map Int (PairInt a)
    smaller)
              | Int
    to Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    <= Int
    p ->
                ( Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap Map Int (PairInt a)
    maybeOverlapping
                , Maybe ((Int, PairInt a), (Int, PairInt a))
    forall a. Maybe a
    Nothing
                , Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap Map Int (PairInt a)
    larger
                )
              | Bool
    otherwise ->
                -- Here from < p < to.
                ( Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert Int
    from (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair Int
    p a
    m) Map Int (PairInt a)
    smaller)
                , ((Int, PairInt a), (Int, PairInt a))
    -> Maybe ((Int, PairInt a), (Int, PairInt a))
    forall a. a -> Maybe a
    Just ((Int
    from, Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair Int
    p a
    m), (Int
    p, Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair Int
    to a
    m))
                , Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert Int
    p (Int -> a -> PairInt a
    forall a. Int -> a -> PairInt a
    pair Int
    to a
    m) Map Int (PairInt a)
    larger)
                )
      where
      (Map Int (PairInt a)
    maybeOverlapping, Maybe (PairInt a)
    equal, Map Int (PairInt a)
    larger) = Int
    -> Map Int (PairInt a)
    -> (Map Int (PairInt a), Maybe (PairInt a), Map Int (PairInt a))
    forall k a. Ord k => k -> Map k a -> (Map k a, Maybe a, Map k a)
    Map.splitLookup Int
    p Map Int (PairInt a)
    f

    -- | Returns a 'RangeMap' overlapping the given range, as well as the
    -- rest of the map.

    insideAndOutside :: Range -> RangeMap a -> (RangeMap a, RangeMap a)
    insideAndOutside :: forall a. Range -> RangeMap a -> (RangeMap a, RangeMap a)
    insideAndOutside Range
    r RangeMap a
    f
      | Range -> Int
    from Range
    r Int -> Int -> Bool
    forall a. Eq a => a -> a -> Bool
    == Range -> Int
    to Range
    r = (RangeMap a
    forall a. Null a => a
    empty, RangeMap a
    f)
      | Bool
    otherwise      =
        ( RangeMap a
    middle
        , -- Because it takes so long to recompile Agda with all
          -- optimisations and run a benchmark no experimental
          -- verification has been made that the code below is better than
          -- reasonable variants. Perhaps it would make sense to benchmark
          -- RangeMap independently of Agda.
          if RangeMap a -> Int
    forall a. RangeMap a -> Int
    size RangeMap a
    before Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    < RangeMap a -> Int
    forall a. RangeMap a -> Int
    size RangeMap a
    middle Bool -> Bool -> Bool
    || RangeMap a -> Int
    forall a. RangeMap a -> Int
    size RangeMap a
    after Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    < RangeMap a -> Int
    forall a. RangeMap a -> Int
    size RangeMap a
    middle then
            Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Map Int (PairInt a) -> RangeMap a)
    -> Map Int (PairInt a) -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $ Map Int (PairInt a) -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => Map k a -> Map k a -> Map k a
    Map.union (RangeMap a -> Map Int (PairInt a)
    forall a. RangeMap a -> Map Int (PairInt a)
    rangeMap RangeMap a
    before) (RangeMap a -> Map Int (PairInt a)
    forall a. RangeMap a -> Map Int (PairInt a)
    rangeMap RangeMap a
    after)
          else
            -- If the number of pieces in the middle is "small", remove
            -- the pieces from f instead of merging before and after.
            Map Int (PairInt a) -> RangeMap a
    forall a. Map Int (PairInt a) -> RangeMap a
    RangeMap (Map Int (PairInt a) -> RangeMap a)
    -> Map Int (PairInt a) -> RangeMap a
    forall a b. (a -> b) -> a -> b
    $
            (Map Int (PairInt a) -> Map Int (PairInt a))
    -> (((Int, PairInt a), (Int, PairInt a))
        -> Map Int (PairInt a) -> Map Int (PairInt a))
    -> Maybe ((Int, PairInt a), (Int, PairInt a))
    -> Map Int (PairInt a)
    -> Map Int (PairInt a)
    forall b a. b -> (a -> b) -> Maybe a -> b
    maybe Map Int (PairInt a) -> Map Int (PairInt a)
    forall a. a -> a
    id ((Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a))
    -> (Int, PairInt a) -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall a b c. (a -> b -> c) -> (a, b) -> c
    uncurry Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert ((Int, PairInt a) -> Map Int (PairInt a) -> Map Int (PairInt a))
    -> (((Int, PairInt a), (Int, PairInt a)) -> (Int, PairInt a))
    -> ((Int, PairInt a), (Int, PairInt a))
    -> Map Int (PairInt a)
    -> Map Int (PairInt a)
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ((Int, PairInt a), (Int, PairInt a)) -> (Int, PairInt a)
    forall a b. (a, b) -> b
    snd) Maybe ((Int, PairInt a), (Int, PairInt a))
    split1 (Map Int (PairInt a) -> Map Int (PairInt a))
    -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall a b. (a -> b) -> a -> b
    $
            (Map Int (PairInt a) -> Map Int (PairInt a))
    -> (((Int, PairInt a), (Int, PairInt a))
        -> Map Int (PairInt a) -> Map Int (PairInt a))
    -> Maybe ((Int, PairInt a), (Int, PairInt a))
    -> Map Int (PairInt a)
    -> Map Int (PairInt a)
    forall b a. b -> (a -> b) -> Maybe a -> b
    maybe Map Int (PairInt a) -> Map Int (PairInt a)
    forall a. a -> a
    id ((Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a))
    -> (Int, PairInt a) -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall a b c. (a -> b -> c) -> (a, b) -> c
    uncurry Int -> PairInt a -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a. Ord k => k -> a -> Map k a -> Map k a
    Map.insert ((Int, PairInt a) -> Map Int (PairInt a) -> Map Int (PairInt a))
    -> (((Int, PairInt a), (Int, PairInt a)) -> (Int, PairInt a))
    -> ((Int, PairInt a), (Int, PairInt a))
    -> Map Int (PairInt a)
    -> Map Int (PairInt a)
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ((Int, PairInt a), (Int, PairInt a)) -> (Int, PairInt a)
    forall a b. (a, b) -> a
    fst) Maybe ((Int, PairInt a), (Int, PairInt a))
    split2 (Map Int (PairInt a) -> Map Int (PairInt a))
    -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall a b. (a -> b) -> a -> b
    $
            Map Int (PairInt a) -> Map Int (PairInt a) -> Map Int (PairInt a)
    forall k a b. Ord k => Map k a -> Map k b -> Map k a
    Map.difference (RangeMap a -> Map Int (PairInt a)
    forall a. RangeMap a -> Map Int (PairInt a)
    rangeMap RangeMap a
    f) (RangeMap a -> Map Int (PairInt a)
    forall a. RangeMap a -> Map Int (PairInt a)
    rangeMap RangeMap a
    middle)
        )
      where
      (RangeMap a
    beforeMiddle, Maybe ((Int, PairInt a), (Int, PairInt a))
    split1, RangeMap a
    after) = Int
    -> RangeMap a
    -> (RangeMap a, Maybe ((Int, PairInt a), (Int, PairInt a)),
        RangeMap a)
    forall a.
    Int
    -> RangeMap a
    -> (RangeMap a, Maybe ((Int, PairInt a), (Int, PairInt a)),
        RangeMap a)
    splitAt' (Range -> Int
    to Range
    r) RangeMap a
    f
      (RangeMap a
    before, Maybe ((Int, PairInt a), (Int, PairInt a))
    split2, RangeMap a
    middle)      = Int
    -> RangeMap a
    -> (RangeMap a, Maybe ((Int, PairInt a), (Int, PairInt a)),
        RangeMap a)
    forall a.
    Int
    -> RangeMap a
    -> (RangeMap a, Maybe ((Int, PairInt a), (Int, PairInt a)),
        RangeMap a)
    splitAt' (Range -> Int
    from Range
    r) RangeMap a
    beforeMiddle

    -- | Restricts the 'RangeMap' to the given range.

    restrictTo :: Range -> RangeMap a -> RangeMap a
    restrictTo :: forall a. Range -> RangeMap a -> RangeMap a
    restrictTo Range
    r = (RangeMap a, RangeMap a) -> RangeMap a
    forall a b. (a, b) -> a
    fst ((RangeMap a, RangeMap a) -> RangeMap a)
    -> (RangeMap a -> (RangeMap a, RangeMap a))
    -> RangeMap a
    -> RangeMap a
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Range -> RangeMap a -> (RangeMap a, RangeMap a)
    forall a. Range -> RangeMap a -> (RangeMap a, RangeMap a)
    insideAndOutside Range
    r