| 1431 | |
| 1432 | template <typename F> |
| 1433 | optional<typename optional_detail::optional_value_type<typename boost::result_of<F(reference_type)>::type>::type> flat_map(F f) & |
| 1434 | { |
| 1435 | if (this->has_value()) |
| 1436 | return f(get()); |
| 1437 | else |
| 1438 | return none; |
| 1439 | } |
| 1440 | |
| 1441 | template <typename F> |
| 1442 | optional<typename optional_detail::optional_value_type<typename boost::result_of<F(reference_const_type)>::type>::type> flat_map(F f) const& |