fix

TikzEditor/MarkovChain.ml

@@ -78,6 +78,10 @@
 
     let get_new_arc_attr atlist _ = []
 
+    let get_new_def_attr _ = []
+    let update_def_attr _ _ _ = None
+    let get_def_attr _ = "",[]
+
     let string_of_attribute = function
       | `Prob arc -> string_of_float arc
       | `StringExpr s -> s

TikzEditor/TikzGraph.ml

@@ -192,6 +192,10 @@ let get_new_arc_attr atlist (p1,p2) =
     ("Node", fun (at,cp) ->  (at , cp @ [`Text (0.5,"node")]),C (List.length cp) )
   ]
 
+let get_new_def_attr _ = []
+let update_def_attr _ _ _ = None
+let get_def_attr _ = "",[]
+
 let print_single_attr f a=
   let open DrawingGeom.Color in
   match is_prefix a "fill=" with