- std::stack<UnfoldingEvent*> event_stack;
- std::vector<UnfoldingEvent*> topological_ordering;
- EventSet unknown_events = events_, temporarily_marked_events, permanently_marked_events;
+ std::stack<const UnfoldingEvent*> event_stack;
+ std::vector<const UnfoldingEvent*> topological_ordering;
+ EventSet unknown_events = events_;
+ EventSet temporarily_marked_events;
+ EventSet permanently_marked_events;