Option(const char* v, OnChange = NULL);
Option(int v, int min, int max, OnChange = NULL);
Option(const char* v, OnChange = NULL);
Option(int v, int min, int max, OnChange = NULL);
std::string value(Value v);
std::string square(Square s);
std::string move(Move m, bool chess960);
std::string value(Value v);
std::string square(Square s);
std::string move(Move m, bool chess960);