static xbt::signal<void(StateEvent&)> on_destruction;
StateEvent(Container* container, Type* type, e_event_type event_type, EntityValue* value, TIData* extra);
~StateEvent() { on_destruction(*this); }
- bool has_extra() { return extra_ != nullptr; }
+ bool has_extra() const { return extra_ != nullptr; }
void print() override;
};