module Data.Fca.Lattice (
Lattice,
Neighborhood (..),
emptyLattice,
appendNeighbors
) where
import Data.HashMap.Strict (HashMap)
import qualified Data.HashMap.Strict as Map
import Data.Monoid
import Data.Fca.Cid (Cid (..))
type Lattice = HashMap Cid Neighborhood
data Neighborhood = Neighborhood { upper :: [Cid],
lower :: [Cid] }
deriving Show
instance Monoid Neighborhood where
mempty = emptyNeighborhood
n1 `mappend` n2 = let Neighborhood u1 l1 = n1
Neighborhood u2 l2 = n2
in Neighborhood (u1 `mappend` u2) (l1 `mappend` l2)
emptyLattice :: Lattice
emptyLattice = Map.empty
emptyNeighborhood :: Neighborhood
emptyNeighborhood = Neighborhood [] []
appendNeighbors :: Lattice -> Cid -> Neighborhood -> Lattice
appendNeighbors lattice cid neighbors =
Map.insertWith mappend cid neighbors lattice