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|
{-# LANGUAGE CPP #-}
#if __GLASGOW_HASKELL__ >= 702
{-# LANGUAGE DeriveGeneric #-}
#endif
-- (c) 1999 - 2002 by Martin Erwig [see file COPYRIGHT]
-- | Tree-based implementation of 'Graph' and 'DynGraph'
--
-- You will probably have better performance using the
-- "Data.Graph.Inductive.PatriciaTree" implementation instead.
module Data.Graph.Inductive.Tree (Gr,UGr) where
import Data.Graph.Inductive.Graph
import Control.Applicative (liftA2)
import Data.List (foldl', sort)
import Data.Map (Map)
import qualified Data.Map as M
import Data.Maybe (fromMaybe)
#if MIN_VERSION_containers (0,4,2)
import Control.DeepSeq (NFData (..))
#endif
#if __GLASGOW_HASKELL__ >= 702
import GHC.Generics (Generic)
#endif
#if MIN_VERSION_base (4,8,0)
import Data.Bifunctor
#else
import Control.Arrow (first, second)
#endif
----------------------------------------------------------------------
-- GRAPH REPRESENTATION
----------------------------------------------------------------------
newtype Gr a b = Gr (GraphRep a b)
#if __GLASGOW_HASKELL__ >= 702
deriving (Generic)
#endif
type GraphRep a b = Map Node (Context' a b)
type Context' a b = (Adj b,a,Adj b)
type UGr = Gr () ()
----------------------------------------------------------------------
-- CLASS INSTANCES
----------------------------------------------------------------------
instance (Eq a, Ord b) => Eq (Gr a b) where
(Gr g1) == (Gr g2) = fmap sortAdj g1 == fmap sortAdj g2
where
sortAdj (p,n,s) = (sort p,n,sort s)
instance (Show a, Show b) => Show (Gr a b) where
showsPrec d g = showParen (d > 10) $
showString "mkGraph "
. shows (labNodes g)
. showString " "
. shows (labEdges g)
instance (Read a, Read b) => Read (Gr a b) where
readsPrec p = readParen (p > 10) $ \ r -> do
("mkGraph", s) <- lex r
(ns,t) <- reads s
(es,u) <- reads t
return (mkGraph ns es, u)
-- Graph
--
instance Graph Gr where
empty = Gr M.empty
isEmpty (Gr g) = M.null g
match v gr@(Gr g) = maybe (Nothing, gr)
(first Just . uncurry (cleanSplit v))
. (\(m,g') -> fmap (flip (,) g') m)
$ M.updateLookupWithKey (const (const Nothing)) v g
mkGraph vs es = insEdges es
. Gr
. M.fromList
. map (second (\l -> ([],l,[])))
$ vs
labNodes (Gr g) = map (\(v,(_,l,_))->(v,l)) (M.toList g)
matchAny (Gr g) = maybe (error "Match Exception, Empty Graph")
(uncurry (uncurry cleanSplit))
(M.minViewWithKey g)
noNodes (Gr g) = M.size g
nodeRange (Gr g) = fromMaybe (error "nodeRange of empty graph")
$ liftA2 (,) (ix (M.minViewWithKey g))
(ix (M.maxViewWithKey g))
where
ix = fmap (fst . fst)
labEdges (Gr g) = concatMap (\(v,(_,_,s))->map (\(l,w)->(v,w,l)) s) (M.toList g)
-- After a Node (with its corresponding Context') are split out of a
-- GraphRep, clean up the remainders.
cleanSplit :: Node -> Context' a b -> GraphRep a b
-> (Context a b, Gr a b)
cleanSplit v (p,l,s) g = (c, Gr g')
where
-- Note: loops are kept only in successor list
c = (p', v, l, s)
p' = rmLoops p
s' = rmLoops s
rmLoops = filter ((/=v) . snd)
g' = updAdj s' (clearPred v) . updAdj p' (clearSucc v) $ g
-- DynGraph
--
instance DynGraph Gr where
(p,v,l,s) & (Gr g) = Gr
. updAdj p (addSucc v)
. updAdj s (addPred v)
$ M.alter addCntxt v g
where
addCntxt = maybe (Just cntxt')
(const (error ("Node Exception, Node: "++show v)))
cntxt' = (p,l,s)
#if MIN_VERSION_containers (0,4,2)
instance (NFData a, NFData b) => NFData (Gr a b) where
rnf (Gr g) = rnf g
#endif
instance Functor (Gr a) where
fmap = emap
#if MIN_VERSION_base (4,8,0)
instance Bifunctor Gr where
bimap = nemap
first = nmap
second = emap
#endif
----------------------------------------------------------------------
-- UTILITIES
----------------------------------------------------------------------
addSucc :: Node -> b -> Context' a b -> Context' a b
addSucc v l (p,l',s) = (p,l',(l,v):s)
addPred :: Node -> b -> Context' a b -> Context' a b
addPred v l (p,l',s) = ((l,v):p,l',s)
clearSucc :: Node -> b -> Context' a b -> Context' a b
clearSucc v _ (p,l,s) = (p,l,filter ((/=v).snd) s)
clearPred :: Node -> b -> Context' a b -> Context' a b
clearPred v _ (p,l,s) = (filter ((/=v).snd) p,l,s)
updAdj :: Adj b -> (b -> Context' a b -> Context' a b) -> GraphRep a b -> GraphRep a b
updAdj adj f g = foldl' (\g' (l,v) -> M.adjust (f l) v g') g adj
|
