mirror of
https://github.com/PurpleI2P/Boost-for-Android-Prebuilt
synced 2025-01-26 06:25:18 +00:00
55 lines
1.5 KiB
C++
55 lines
1.5 KiB
C++
/*!
|
|
@file
|
|
Defines `boost::hana::lift`.
|
|
|
|
@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)
|
|
*/
|
|
|
|
#ifndef BOOST_HANA_LIFT_HPP
|
|
#define BOOST_HANA_LIFT_HPP
|
|
|
|
#include <boost/hana/fwd/lift.hpp>
|
|
|
|
#include <boost/hana/concept/applicative.hpp>
|
|
#include <boost/hana/concept/sequence.hpp>
|
|
#include <boost/hana/config.hpp>
|
|
#include <boost/hana/core/dispatch.hpp>
|
|
#include <boost/hana/core/make.hpp>
|
|
|
|
|
|
BOOST_HANA_NAMESPACE_BEGIN
|
|
//! @cond
|
|
template <typename A>
|
|
template <typename X>
|
|
constexpr auto lift_t<A>::operator()(X&& x) const {
|
|
#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
|
|
static_assert(hana::Applicative<A>::value,
|
|
"hana::lift<A> requires 'A' to be an Applicative");
|
|
#endif
|
|
|
|
using Lift = BOOST_HANA_DISPATCH_IF(lift_impl<A>,
|
|
hana::Applicative<A>::value
|
|
);
|
|
|
|
return Lift::apply(static_cast<X&&>(x));
|
|
}
|
|
//! @endcond
|
|
|
|
template <typename A, bool condition>
|
|
struct lift_impl<A, when<condition>> : default_ {
|
|
template <typename ...Args>
|
|
static constexpr auto apply(Args&& ...args) = delete;
|
|
};
|
|
|
|
template <typename S>
|
|
struct lift_impl<S, when<Sequence<S>::value>> {
|
|
template <typename X>
|
|
static constexpr decltype(auto) apply(X&& x)
|
|
{ return hana::make<S>(static_cast<X&&>(x)); }
|
|
};
|
|
BOOST_HANA_NAMESPACE_END
|
|
|
|
#endif // !BOOST_HANA_LIFT_HPP
|