Index: Dynamic.hs
===================================================================
RCS file: /cvs/fptools/libraries/base/Data/Dynamic.hs,v
retrieving revision 1.28
diff -u -r1.28 Dynamic.hs
--- Dynamic.hs	11 Jan 2005 16:04:10 -0000	1.28
+++ Dynamic.hs	4 Mar 2005 07:23:16 -0000
@@ -34,7 +34,8 @@
 	
 	-- * Applying functions of dynamic type
 	dynApply,
-	dynApp
+	dynApp,
+        dynTypeRep
 
   ) where
 
@@ -162,3 +163,8 @@
              Nothing -> error ("Type error in dynamic application.\n" ++
                                "Can't apply function " ++ show f ++
                                " to argument " ++ show x)
+
+dynTypeRep :: Dynamic -> TypeRep
+dynTypeRep (Dynamic tr _) = tr 
+
+
Index: Typeable.hs
===================================================================
RCS file: /cvs/fptools/libraries/base/Data/Typeable.hs,v
retrieving revision 1.34
diff -u -r1.34 Typeable.hs
--- Typeable.hs	2 Feb 2005 14:54:18 -0000	1.34
+++ Typeable.hs	4 Mar 2005 07:23:16 -0000
@@ -77,7 +77,8 @@
 	typeOf3Default,	-- :: (Typeable4 t, Typeable a) => t a b c d -> TypeRep
 	typeOf4Default,	-- :: (Typeable5 t, Typeable a) => t a b c d e -> TypeRep
 	typeOf5Default,	-- :: (Typeable6 t, Typeable a) => t a b c d e f -> TypeRep
-	typeOf6Default	-- :: (Typeable7 t, Typeable a) => t a b c d e f g -> TypeRep
+	typeOf6Default, -- :: (Typeable7 t, Typeable a) => t a b c d e f g -> TypeRep
+        typeRepIndex
 
   ) where
 
@@ -652,3 +653,11 @@
 
 appKeys :: Key -> [Key] -> Key
 appKeys k ks = foldl appKey k ks
+
+-- | This can be used for creation of efficient maps or hash tables based on TypeReps. 
+-- It is in IO because the numbering may differ between runs of a program.
+
+ 
+typeRepIndex :: TypeRep -> IO Int 
+typeRepIndex (TypeRep (Key i) _ _) = return i 
+