mirror of
https://github.com/boostorg/hana.git
synced 2026-01-19 04:12:12 +00:00
64 lines
2.0 KiB
C++
64 lines
2.0 KiB
C++
// Copyright Louis Dionne 2013-2022
|
|
// Distributed under the Boost Software License, Version 1.0.
|
|
// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
|
|
|
|
#include <boost/hana/assert.hpp>
|
|
#include <boost/hana/config.hpp>
|
|
#include <boost/hana/core/to.hpp>
|
|
#include <boost/hana/equal.hpp>
|
|
#include <boost/hana/find.hpp>
|
|
#include <boost/hana/functional/id.hpp>
|
|
#include <boost/hana/fwd/accessors.hpp>
|
|
#include <boost/hana/integral_constant.hpp>
|
|
#include <boost/hana/not_equal.hpp>
|
|
#include <boost/hana/pair.hpp>
|
|
#include <boost/hana/string.hpp>
|
|
#include <boost/hana/tuple.hpp>
|
|
|
|
#include <string>
|
|
#include <utility>
|
|
namespace hana = boost::hana;
|
|
|
|
|
|
//! [main]
|
|
struct Person {
|
|
std::string name;
|
|
int age;
|
|
};
|
|
|
|
// The keys can be anything as long as they are compile-time comparable.
|
|
constexpr auto name = hana::integral_c<std::string Person::*, &Person::name>;
|
|
constexpr auto age = hana::string_c<'a', 'g', 'e'>;
|
|
|
|
namespace boost { namespace hana {
|
|
template <>
|
|
struct accessors_impl<Person> {
|
|
static BOOST_HANA_CONSTEXPR_LAMBDA auto apply() {
|
|
return make_tuple(
|
|
make_pair(name, [](auto&& p) -> decltype(auto) {
|
|
return id(std::forward<decltype(p)>(p).name);
|
|
}),
|
|
make_pair(age, [](auto&& p) -> decltype(auto) {
|
|
return id(std::forward<decltype(p)>(p).age);
|
|
})
|
|
);
|
|
}
|
|
};
|
|
}}
|
|
//! [main]
|
|
|
|
int main() {
|
|
Person john{"John", 30}, bob{"Bob", 40};
|
|
BOOST_HANA_RUNTIME_CHECK(hana::equal(john, john));
|
|
BOOST_HANA_RUNTIME_CHECK(hana::not_equal(john, bob));
|
|
|
|
BOOST_HANA_RUNTIME_CHECK(hana::find(john, name) == hana::just("John"));
|
|
BOOST_HANA_RUNTIME_CHECK(hana::find(john, age) == hana::just(30));
|
|
BOOST_HANA_CONSTANT_CHECK(hana::find(john, BOOST_HANA_STRING("foo")) == hana::nothing);
|
|
|
|
BOOST_HANA_RUNTIME_CHECK(hana::to_tuple(john) == hana::make_tuple(
|
|
hana::make_pair(name, "John"),
|
|
hana::make_pair(age, 30)
|
|
));
|
|
}
|