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| author | krasimir <krasimir@chalmers.se> | 2009-12-13 18:50:29 +0000 |
|---|---|---|
| committer | krasimir <krasimir@chalmers.se> | 2009-12-13 18:50:29 +0000 |
| commit | f85232947e74ee7ef8c7b0ad2338212e7e68f1be (patch) | |
| tree | 667b886a5e3a4b026a63d4e3597f32497d824761 /src/compiler/GF/Data/Graph.hs | |
| parent | d88a865faff59c98fc91556ff8700b10ee5f2df8 (diff) | |
reorganize the directories under src, and rescue the JavaScript interpreter from deprecated
Diffstat (limited to 'src/compiler/GF/Data/Graph.hs')
| -rw-r--r-- | src/compiler/GF/Data/Graph.hs | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/src/compiler/GF/Data/Graph.hs b/src/compiler/GF/Data/Graph.hs new file mode 100644 index 000000000..bfb289860 --- /dev/null +++ b/src/compiler/GF/Data/Graph.hs @@ -0,0 +1,178 @@ +---------------------------------------------------------------------- +-- | +-- Module : Graph +-- Maintainer : BB +-- Stability : (stable) +-- Portability : (portable) +-- +-- > CVS $Date: 2005/11/10 16:43:44 $ +-- > CVS $Author: bringert $ +-- > CVS $Revision: 1.2 $ +-- +-- A simple graph module. +----------------------------------------------------------------------------- +module GF.Data.Graph ( Graph(..), Node, Edge, NodeInfo + , newGraph, nodes, edges + , nmap, emap, newNode, newNodes, newEdge, newEdges + , insertEdgeWith + , removeNode, removeNodes + , nodeInfo + , getIncoming, getOutgoing, getNodeLabel + , inDegree, outDegree + , nodeLabel + , edgeFrom, edgeTo, edgeLabel + , reverseGraph, mergeGraphs, renameNodes + ) where + +import GF.Data.Utilities + +import Data.List +import Data.Maybe +import Data.Map (Map) +import qualified Data.Map as Map +import Data.Set (Set) +import qualified Data.Set as Set + +data Graph n a b = Graph [n] ![Node n a] ![Edge n b] + deriving (Eq,Show) + +type Node n a = (n,a) +type Edge n b = (n,n,b) + +type NodeInfo n a b = Map n (a, [Edge n b], [Edge n b]) + +-- | Create a new empty graph. +newGraph :: [n] -> Graph n a b +newGraph ns = Graph ns [] [] + +-- | Get all the nodes in the graph. +nodes :: Graph n a b -> [Node n a] +nodes (Graph _ ns _) = ns + +-- | Get all the edges in the graph. +edges :: Graph n a b -> [Edge n b] +edges (Graph _ _ es) = es + +-- | Map a function over the node labels. +nmap :: (a -> c) -> Graph n a b -> Graph n c b +nmap f (Graph c ns es) = Graph c [(n,f l) | (n,l) <- ns] es + +-- | Map a function over the edge labels. +emap :: (b -> c) -> Graph n a b -> Graph n a c +emap f (Graph c ns es) = Graph c ns [(x,y,f l) | (x,y,l) <- es] + +-- | Add a node to the graph. +newNode :: a -- ^ Node label + -> Graph n a b + -> (Graph n a b,n) -- ^ Node graph and name of new node +newNode l (Graph (c:cs) ns es) = (Graph cs ((c,l):ns) es, c) + +newNodes :: [a] -> Graph n a b -> (Graph n a b,[Node n a]) +newNodes ls g = (g', zip ns ls) + where (g',ns) = mapAccumL (flip newNode) g ls +-- lazy version: +--newNodes ls (Graph cs ns es) = (Graph cs' (ns'++ns) es, ns') +-- where (xs,cs') = splitAt (length ls) cs +-- ns' = zip xs ls + +newEdge :: Edge n b -> Graph n a b -> Graph n a b +newEdge e (Graph c ns es) = Graph c ns (e:es) + +newEdges :: [Edge n b] -> Graph n a b -> Graph n a b +newEdges es g = foldl' (flip newEdge) g es +-- lazy version: +-- newEdges es' (Graph c ns es) = Graph c ns (es'++es) + +insertEdgeWith :: Eq n => + (b -> b -> b) -> Edge n b -> Graph n a b -> Graph n a b +insertEdgeWith f e@(x,y,l) (Graph c ns es) = Graph c ns (h es) + where h [] = [e] + h (e'@(x',y',l'):es') | x' == x && y' == y = (x',y', f l l'):es' + | otherwise = e':h es' + +-- | Remove a node and all edges to and from that node. +removeNode :: Ord n => n -> Graph n a b -> Graph n a b +removeNode n = removeNodes (Set.singleton n) + +-- | Remove a set of nodes and all edges to and from those nodes. +removeNodes :: Ord n => Set n -> Graph n a b -> Graph n a b +removeNodes xs (Graph c ns es) = Graph c ns' es' + where + keepNode n = not (Set.member n xs) + ns' = [ x | x@(n,_) <- ns, keepNode n ] + es' = [ e | e@(f,t,_) <- es, keepNode f && keepNode t ] + +-- | Get a map of node names to info about each node. +nodeInfo :: Ord n => Graph n a b -> NodeInfo n a b +nodeInfo g = Map.fromList [ (n, (x, fn inc n, fn out n)) | (n,x) <- nodes g ] + where + inc = groupEdgesBy edgeTo g + out = groupEdgesBy edgeFrom g + fn m n = fromMaybe [] (Map.lookup n m) + +groupEdgesBy :: (Ord n) => (Edge n b -> n) -- ^ Gets the node to group by + -> Graph n a b -> Map n [Edge n b] +groupEdgesBy f g = Map.fromListWith (++) [(f e, [e]) | e <- edges g] + +lookupNode :: Ord n => NodeInfo n a b -> n -> (a, [Edge n b], [Edge n b]) +lookupNode i n = fromJust $ Map.lookup n i + +getIncoming :: Ord n => NodeInfo n a b -> n -> [Edge n b] +getIncoming i n = let (_,inc,_) = lookupNode i n in inc + +getOutgoing :: Ord n => NodeInfo n a b -> n -> [Edge n b] +getOutgoing i n = let (_,_,out) = lookupNode i n in out + +inDegree :: Ord n => NodeInfo n a b -> n -> Int +inDegree i n = length $ getIncoming i n + +outDegree :: Ord n => NodeInfo n a b -> n -> Int +outDegree i n = length $ getOutgoing i n + +getNodeLabel :: Ord n => NodeInfo n a b -> n -> a +getNodeLabel i n = let (l,_,_) = lookupNode i n in l + +nodeLabel :: Node n a -> a +nodeLabel = snd + +edgeFrom :: Edge n b -> n +edgeFrom (f,_,_) = f + +edgeTo :: Edge n b -> n +edgeTo (_,t,_) = t + +edgeLabel :: Edge n b -> b +edgeLabel (_,_,l) = l + +reverseGraph :: Graph n a b -> Graph n a b +reverseGraph (Graph c ns es) = Graph c ns [ (t,f,l) | (f,t,l) <- es ] + +-- | Add the nodes from the second graph to the first graph. +-- The nodes in the second graph will be renamed using the name +-- supply in the first graph. +-- This function is more efficient when the second graph +-- is smaller than the first. +mergeGraphs :: Ord m => Graph n a b -> Graph m a b + -> (Graph n a b, m -> n) -- ^ The new graph and a function translating + -- the old names of nodes in the second graph + -- to names in the new graph. +mergeGraphs (Graph c ns1 es1) g2 = (Graph c' (ns2++ns1) (es2++es1), newName) + where + (xs,c') = splitAt (length (nodes g2)) c + newNames = Map.fromList (zip (map fst (nodes g2)) xs) + newName n = fromJust $ Map.lookup n newNames + Graph _ ns2 es2 = renameNodes newName undefined g2 + +-- | Rename the nodes in the graph. +renameNodes :: (n -> m) -- ^ renaming function + -> [m] -- ^ infinite supply of fresh node names, to + -- use when adding nodes in the future. + -> Graph n a b -> Graph m a b +renameNodes newName c (Graph _ ns es) = Graph c ns' es' + where ns' = map' (\ (n,x) -> (newName n,x)) ns + es' = map' (\ (f,t,l) -> (newName f, newName t, l)) es + +-- | A strict 'map' +map' :: (a -> b) -> [a] -> [b] +map' _ [] = [] +map' f (x:xs) = ((:) $! f x) $! map' f xs |
