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diff --git a/src-3.0/GF/Visualization/Graphviz.hs b/src-3.0/GF/Visualization/Graphviz.hs
new file mode 100644
index 000000000..b59e3ecd2
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+++ b/src-3.0/GF/Visualization/Graphviz.hs
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+----------------------------------------------------------------------
+-- |
+-- 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.Visualization.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