Index: src/SynTree/Label.h
===================================================================
--- src/SynTree/Label.h	(revision 6b0b624129f6017f7706b516a24a52e382e3a334)
+++ src/SynTree/Label.h	(revision 804b57e31aa94e0c84b8dbfd4fb6997a6e25868a)
@@ -33,5 +33,5 @@
 	std::list< Attribute * >& get_attributes() { return attributes; }
 
-	operator std::string() { return name; }
+	operator std::string() const { return name; }
 	bool empty() { return name.empty(); }
   private: