Added Show instance for the graph

1 files changed, 14 insertions, 2 deletions

diff --git a/ProofGraph.hs b/ProofGraph.hs
index 0cd2e7e..6459591 100644
--- a/ProofGraph.hs
+++ b/ProofGraph.hs
@@ -10,16 +10,28 @@ module ProofGraph (
 
 import Data.Set( Set )
 import qualified Data.Set as Set
+import qualified Data.List as List
 
 
 
 data Node a = Node { contents :: a
-                   , successors :: Set (Node a) } deriving (Eq, Ord, Show)
+                   , successors :: Set (Node a) } deriving (Eq, Ord)
 
-data Graph a = Graph { nodes :: Set (Node a) } deriving (Show)
+data Graph a = Graph { nodes :: Set (Node a) }
 
 
 
+instance (Show a, Eq a) => Show (Node a) where
+	show x   =   let header = "ID: " ++ (show . contents $ x)
+	                 footer = if ((successors x) == Set.empty)
+	                 	      then "\n"
+	                 	      else " -> " ++ List.intercalate ", " (map (show . contents) (Set.toList . successors $ x)) ++ "\n"
+	             in header ++ footer
+
+instance (Show a, Eq a) => Show (Graph a) where
+	show x   =   "Graph: \n" ++ List.foldl' (++) [] (map show (Set.toList . nodes $ x)) ++ "\n"
+
+
 empty :: Graph a
 empty = Graph Set.empty