mirror of
https://github.com/ecency/ecency-mobile.git
synced 2024-12-26 06:42:15 +03:00
49 lines
1.4 KiB
C++
49 lines
1.4 KiB
C++
/*!
|
|
@file
|
|
Defines `boost::hana::duplicate`.
|
|
|
|
@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_DUPLICATE_HPP
|
|
#define BOOST_HANA_DUPLICATE_HPP
|
|
|
|
#include <boost/hana/fwd/duplicate.hpp>
|
|
|
|
#include <boost/hana/concept/comonad.hpp>
|
|
#include <boost/hana/config.hpp>
|
|
#include <boost/hana/core/dispatch.hpp>
|
|
#include <boost/hana/extend.hpp>
|
|
#include <boost/hana/functional/id.hpp>
|
|
|
|
|
|
BOOST_HANA_NAMESPACE_BEGIN
|
|
//! @cond
|
|
template <typename W_>
|
|
constexpr decltype(auto) duplicate_t::operator()(W_&& w) const {
|
|
using W = typename hana::tag_of<W_>::type;
|
|
using Duplicate = BOOST_HANA_DISPATCH_IF(duplicate_impl<W>,
|
|
hana::Comonad<W>::value
|
|
);
|
|
|
|
#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
|
|
static_assert(hana::Comonad<W>::value,
|
|
"hana::duplicate(w) requires 'w' to be a Comonad");
|
|
#endif
|
|
|
|
return Duplicate::apply(static_cast<W_&&>(w));
|
|
}
|
|
//! @endcond
|
|
|
|
template <typename W, bool condition>
|
|
struct duplicate_impl<W, when<condition>> : default_ {
|
|
template <typename X>
|
|
static constexpr decltype(auto) apply(X&& x)
|
|
{ return hana::extend(static_cast<X&&>(x), hana::id); }
|
|
};
|
|
BOOST_HANA_NAMESPACE_END
|
|
|
|
#endif // !BOOST_HANA_DUPLICATE_HPP
|