mirror of
https://github.com/ecency/ecency-mobile.git
synced 2024-12-23 13:22:02 +03:00
49 lines
1.3 KiB
C++
49 lines
1.3 KiB
C++
/*!
|
|
@file
|
|
Defines `boost::hana::keys`.
|
|
|
|
@copyright Louis Dionne 2013-2016
|
|
Distributed under the Boost Software License, Version 1.0.
|
|
(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
|
|
*/
|
|
|
|
#ifndef BOOST_HANA_KEYS_HPP
|
|
#define BOOST_HANA_KEYS_HPP
|
|
|
|
#include <boost/hana/fwd/keys.hpp>
|
|
|
|
#include <boost/hana/accessors.hpp>
|
|
#include <boost/hana/concept/struct.hpp>
|
|
#include <boost/hana/config.hpp>
|
|
#include <boost/hana/core/dispatch.hpp>
|
|
#include <boost/hana/first.hpp>
|
|
#include <boost/hana/transform.hpp>
|
|
|
|
|
|
BOOST_HANA_NAMESPACE_BEGIN
|
|
//! @cond
|
|
template <typename Map>
|
|
constexpr auto keys_t::operator()(Map&& map) const {
|
|
return keys_impl<typename hana::tag_of<Map>::type>::apply(
|
|
static_cast<Map&&>(map)
|
|
);
|
|
}
|
|
//! @endcond
|
|
|
|
template <typename T, bool condition>
|
|
struct keys_impl<T, when<condition>> : default_ {
|
|
template <typename ...Args>
|
|
static constexpr auto apply(Args&& ...) = delete;
|
|
};
|
|
|
|
template <typename S>
|
|
struct keys_impl<S, when<hana::Struct<S>::value>> {
|
|
template <typename Object>
|
|
static constexpr auto apply(Object const&) {
|
|
return hana::transform(hana::accessors<S>(), hana::first);
|
|
}
|
|
};
|
|
BOOST_HANA_NAMESPACE_END
|
|
|
|
#endif // !BOOST_HANA_KEYS_HPP
|