3 files changed, 424 insertions, 0 deletions
diff --git a/src/GF/Data/Graph.hs b/src/GF/Data/Graph.hs
new file mode 100644
index 000000000..bfb289860
--- /dev/null
+++ b/src/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
diff --git a/src/GF/Data/Graphviz.hs b/src/GF/Data/Graphviz.hs
new file mode 100644
index 000000000..411f76898
--- /dev/null
+++ b/src/GF/Data/Graphviz.hs
@@ -0,0 +1,116 @@
+----------------------------------------------------------------------
+-- |
+-- Module      : Graphviz
+-- Maintainer  : BB
+-- Stability   : (stable)
+-- Portability : (portable)
+--
+-- > CVS $Date: 2005/09/15 18:10:44 $ 
+-- > CVS $Author: bringert $
+-- > CVS $Revision: 1.2 $
+--
+-- Graphviz DOT format representation and printing.
+-----------------------------------------------------------------------------
+
+module GF.Data.Graphviz (
+				  Graph(..), GraphType(..), 
+				  Node(..), Edge(..),
+				  Attr,
+                                  addSubGraphs,
+                                  setName,
+                                  setAttr,
+				  prGraphviz
+			) where
+
+import Data.Char
+
+import GF.Data.Utilities
+
+-- | Graph type, graph ID, graph attirbutes, graph nodes, graph edges, subgraphs
+data Graph = Graph {
+                    gType :: GraphType,
+                    gId :: Maybe String,
+                    gAttrs :: [Attr],
+                    gNodes :: [Node],
+                    gEdges :: [Edge],
+                    gSubgraphs :: [Graph]
+                   }
+  deriving (Show)
+
+data GraphType = Directed | Undirected
+  deriving (Show)
+
+data Node = Node String [Attr]
+  deriving Show
+
+data Edge = Edge String String [Attr]
+  deriving Show
+
+type Attr = (String,String)
+
+--
+-- * Graph construction
+--
+
+addSubGraphs :: [Graph] -> Graph -> Graph
+addSubGraphs gs g = g { gSubgraphs = gs ++ gSubgraphs g }
+
+setName :: String -> Graph -> Graph
+setName n g = g { gId = Just n }
+
+setAttr :: String -> String -> Graph -> Graph
+setAttr n v g = g { gAttrs = tableSet n v (gAttrs g) }
+
+--
+-- * Pretty-printing
+--
+
+prGraphviz :: Graph -> String
+prGraphviz g@(Graph t i _ _ _ _) =
+    graphtype t ++ " " ++ maybe "" esc i ++ " {\n" ++ prGraph g ++ "}\n"
+
+prSubGraph :: Graph -> String
+prSubGraph g@(Graph _ i _ _ _ _) = 
+    "subgraph" ++ " " ++ maybe "" esc i ++ " {\n" ++ prGraph g ++ "}"
+
+prGraph :: Graph -> String
+prGraph (Graph t id at ns es ss) = 
+    unlines $ map (++";") (map prAttr at
+		           ++ map prNode ns 
+		           ++ map (prEdge t) es
+                           ++ map prSubGraph ss)
+
+graphtype :: GraphType -> String
+graphtype Directed = "digraph"
+graphtype Undirected = "graph"
+
+prNode :: Node -> String
+prNode (Node n at) = esc n ++ " " ++ prAttrList at
+
+prEdge :: GraphType -> Edge -> String
+prEdge t (Edge x y at) = esc x ++ " " ++ edgeop t ++ " " ++ esc y ++ " " ++ prAttrList at
+
+edgeop :: GraphType -> String
+edgeop Directed = "->"
+edgeop Undirected = "--"
+
+prAttrList :: [Attr] -> String
+prAttrList [] = ""
+prAttrList at =	"[" ++ join "," (map prAttr at) ++ "]"
+
+prAttr :: Attr -> String
+prAttr (n,v) = esc n ++ " = " ++ esc v
+
+esc :: String -> String
+esc s | needEsc s = "\"" ++ concat [ if shouldEsc c then ['\\',c] else [c] | c <- s ] ++ "\""
+      | otherwise = s
+  where shouldEsc = (`elem` ['"', '\\'])
+
+needEsc :: String -> Bool
+needEsc [] = True
+needEsc xs | all isDigit xs = False
+needEsc (x:xs) = not (isIDFirst x && all isIDChar xs)
+
+isIDFirst, isIDChar :: Char -> Bool
+isIDFirst c = c `elem` (['_']++['a'..'z']++['A'..'Z'])
+isIDChar c = isIDFirst c || isDigit c
diff --git a/src/GF/Data/Relation.hs b/src/GF/Data/Relation.hs
new file mode 100644
index 000000000..1a052ec68
--- /dev/null
+++ b/src/GF/Data/Relation.hs
@@ -0,0 +1,130 @@
+----------------------------------------------------------------------
+-- |
+-- Module      : Relation
+-- Maintainer  : BB
+-- Stability   : (stable)
+-- Portability : (portable)
+--
+-- > CVS $Date: 2005/10/26 17:13:13 $ 
+-- > CVS $Author: bringert $
+-- > CVS $Revision: 1.1 $
+--
+-- A simple module for relations.
+-----------------------------------------------------------------------------
+
+module GF.Data.Relation (Rel, mkRel, mkRel'
+                           , allRelated , isRelatedTo
+                           , transitiveClosure
+                           , reflexiveClosure, reflexiveClosure_
+                           , symmetricClosure
+                           , symmetricSubrelation, reflexiveSubrelation
+                           , reflexiveElements
+                           , equivalenceClasses
+                           , isTransitive, isReflexive, isSymmetric
+                           , isEquivalence
+                           , isSubRelationOf) where
+
+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
+
+import GF.Data.Utilities
+
+type Rel a = Map a (Set a)
+
+-- | Creates a relation from a list of related pairs.
+mkRel :: Ord a => [(a,a)] -> Rel a
+mkRel ps = relates ps Map.empty
+
+-- | Creates a relation from a list pairs of elements and the elements
+--   related to them.
+mkRel' :: Ord a => [(a,[a])] -> Rel a
+mkRel' xs = Map.fromListWith Set.union [(x,Set.fromList ys) | (x,ys) <- xs]
+
+relToList :: Rel a -> [(a,a)]
+relToList r = [ (x,y) | (x,ys) <- Map.toList r, y <- Set.toList ys ]
+
+-- | Add a pair to the relation.
+relate :: Ord a => a -> a -> Rel a -> Rel a
+relate x y r = Map.insertWith Set.union x (Set.singleton y) r
+
+-- | Add a list of pairs to the relation.
+relates :: Ord a => [(a,a)] -> Rel a -> Rel a
+relates ps r = foldl (\r' (x,y) -> relate x y r') r ps
+
+-- | Checks if an element is related to another.
+isRelatedTo :: Ord a => Rel a -> a  -> a -> Bool
+isRelatedTo r x y = maybe False (y `Set.member`) (Map.lookup x r)
+
+-- | Get the set of elements to which a given element is related.
+allRelated :: Ord a => Rel a -> a -> Set a
+allRelated r x = fromMaybe Set.empty (Map.lookup x r)
+
+-- | Get all elements in the relation.
+domain :: Ord a => Rel a -> Set a
+domain r = foldl Set.union (Map.keysSet r) (Map.elems r)
+
+-- | Keep only pairs for which both elements are in the given set.
+intersectSetRel :: Ord a => Set a -> Rel a -> Rel a
+intersectSetRel s = filterRel (\x y -> x `Set.member` s && y `Set.member` s)
+
+transitiveClosure :: Ord a => Rel a -> Rel a
+transitiveClosure r = fix (Map.map growSet) r
+  where growSet ys = foldl Set.union ys (map (allRelated r) $ Set.toList ys)
+
+reflexiveClosure_ :: Ord a => [a] -- ^ The set over which the relation is defined.
+		 -> Rel a -> Rel a
+reflexiveClosure_ u r = relates [(x,x) | x <- u] r
+
+-- | Uses 'domain'
+reflexiveClosure :: Ord a => Rel a -> Rel a
+reflexiveClosure r = reflexiveClosure_ (Set.toList $ domain r) r
+
+symmetricClosure :: Ord a => Rel a -> Rel a
+symmetricClosure r = relates [ (y,x) | (x,y) <- relToList r ] r
+
+symmetricSubrelation :: Ord a => Rel a -> Rel a
+symmetricSubrelation r = filterRel (flip $ isRelatedTo r) r
+
+reflexiveSubrelation :: Ord a => Rel a -> Rel a
+reflexiveSubrelation r = intersectSetRel (reflexiveElements r) r
+
+-- | Get the set of elements which are related to themselves.
+reflexiveElements :: Ord a => Rel a -> Set a
+reflexiveElements r = Set.fromList [ x | (x,ys) <- Map.toList r, x `Set.member` ys ]
+
+-- | Keep the related pairs for which the predicate is true.
+filterRel :: Ord a => (a -> a -> Bool) -> Rel a -> Rel a 
+filterRel p = purgeEmpty . Map.mapWithKey (Set.filter . p)
+
+-- | Remove keys that map to no elements.
+purgeEmpty :: Ord a => Rel a -> Rel a
+purgeEmpty r = Map.filter (not . Set.null) r
+
+
+-- | Get the equivalence classes from an equivalence relation. 
+equivalenceClasses :: Ord a => Rel a -> [Set a]
+equivalenceClasses r = equivalenceClasses_ (Map.keys r) r
+ where equivalenceClasses_ [] _ = []
+       equivalenceClasses_ (x:xs) r = ys:equivalenceClasses_ zs r
+	   where ys = allRelated r x
+                 zs = [x' | x' <- xs, not (x' `Set.member` ys)]
+
+isTransitive :: Ord a => Rel a -> Bool
+isTransitive r = and [z `Set.member` ys | (x,ys) <- Map.toList r, 
+                      y <- Set.toList ys, z <- Set.toList (allRelated r y)]
+
+isReflexive :: Ord a => Rel a -> Bool
+isReflexive r = all (\ (x,ys) -> x `Set.member` ys) (Map.toList r)
+
+isSymmetric :: Ord a => Rel a -> Bool
+isSymmetric r = and [isRelatedTo r y x | (x,y) <- relToList r]
+
+isEquivalence :: Ord a => Rel a -> Bool
+isEquivalence r = isReflexive r && isSymmetric r && isTransitive r
+
+isSubRelationOf :: Ord a => Rel a -> Rel a -> Bool
+isSubRelationOf r1 r2 = all (uncurry (isRelatedTo r2)) (relToList r1)