Updated Toy, added a couple util functions

core/engine_node.h

@@ -5,9 +5,10 @@
 #include "literal_dictionary.h"
 #include "interpreter.h"
 
+#define OPAQUE_TAG_ENGINE_NODE 1
+
 //forward declare
 typedef struct _engineNode EngineNode;
-
 typedef void (*EngineNodeCallback)(void*);
 
 //the node object, which forms a tree
@@ -18,6 +19,13 @@ typedef struct _engineNode {
 	//toy functions, stored in a dict for flexibility
 	LiteralDictionary* functions;
 
+	//point to the parent
+	EngineNode* parent;
+
+	//my opaque type tag
+	int tag;
+	int _unused;
+
 	//use Toy's memory model
 	EngineNode** children;
 	int capacity;