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Diffstat (limited to 'src/boost/libs/hana/example/struct.mcd.tag_dispatching.cpp')
-rw-r--r-- | src/boost/libs/hana/example/struct.mcd.tag_dispatching.cpp | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/src/boost/libs/hana/example/struct.mcd.tag_dispatching.cpp b/src/boost/libs/hana/example/struct.mcd.tag_dispatching.cpp new file mode 100644 index 000000000..9788e8305 --- /dev/null +++ b/src/boost/libs/hana/example/struct.mcd.tag_dispatching.cpp @@ -0,0 +1,63 @@ +// Copyright Louis Dionne 2013-2017 +// 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) + )); +} |