struct.custom_accessor.cpp 2.0 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768
  1. // Copyright Louis Dionne 2013-2017
  2. // Distributed under the Boost Software License, Version 1.0.
  3. // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
  4. #include <boost/hana/assert.hpp>
  5. #include <boost/hana/config.hpp>
  6. #include <boost/hana/core/to.hpp>
  7. #include <boost/hana/equal.hpp>
  8. #include <boost/hana/find.hpp>
  9. #include <boost/hana/functional/id.hpp>
  10. #include <boost/hana/fwd/accessors.hpp>
  11. #include <boost/hana/integral_constant.hpp>
  12. #include <boost/hana/not_equal.hpp>
  13. #include <boost/hana/pair.hpp>
  14. #include <boost/hana/string.hpp>
  15. #include <boost/hana/tuple.hpp>
  16. #include <string>
  17. #include <utility>
  18. namespace hana = boost::hana;
  19. //! [main]
  20. struct Person {
  21. Person(std::string const& name, int age) : name_(name), age_(age) { }
  22. std::string const& get_name() const { return name_; }
  23. int get_age() const { return age_; }
  24. private:
  25. std::string name_;
  26. int age_;
  27. };
  28. namespace boost { namespace hana {
  29. template <>
  30. struct accessors_impl<Person> {
  31. static BOOST_HANA_CONSTEXPR_LAMBDA auto apply() {
  32. return make_tuple(
  33. make_pair(BOOST_HANA_STRING("name"), [](auto&& p) -> std::string const& {
  34. return p.get_name();
  35. }),
  36. make_pair(BOOST_HANA_STRING("age"), [](auto&& p) {
  37. return p.get_age();
  38. })
  39. );
  40. }
  41. };
  42. }}
  43. //! [main]
  44. int main() {
  45. auto name = BOOST_HANA_STRING("name");
  46. auto age = BOOST_HANA_STRING("age");
  47. Person john{"John", 30}, bob{"Bob", 40};
  48. BOOST_HANA_RUNTIME_CHECK(hana::equal(john, john));
  49. BOOST_HANA_RUNTIME_CHECK(hana::not_equal(john, bob));
  50. BOOST_HANA_RUNTIME_CHECK(hana::find(john, name) == hana::just("John"));
  51. BOOST_HANA_RUNTIME_CHECK(hana::find(john, age) == hana::just(30));
  52. BOOST_HANA_CONSTANT_CHECK(hana::find(john, BOOST_HANA_STRING("foo")) == hana::nothing);
  53. BOOST_HANA_RUNTIME_CHECK(hana::to_tuple(john) == hana::make_tuple(
  54. hana::make_pair(name, "John"),
  55. hana::make_pair(age, 30)
  56. ));
  57. }