-using stack_t = std::list<std::shared_ptr<State>>;
-
-/* Used to compare two stacks and decide which one is better to backtrack,
- * regarding the chosen guide in the last state. */
-class OpenedStatesCompare {
-public:
- bool operator()(std::shared_ptr<State> const& lhs, std::shared_ptr<State> const& rhs) const
- {
- return lhs->next_transition_guided().second > rhs->next_transition_guided().second;
- }
-};