projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | /*! |
| 2 | @file | |
| 3 | Defines `boost::hana::transform`. | |
| 4 | ||
| 5 | @copyright Louis Dionne 2013-2016 | |
| 6 | Distributed under the Boost Software License, Version 1.0. | |
| 7 | (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) | |
| 8 | */ | |
| 9 | ||
| 10 | #ifndef BOOST_HANA_TRANSFORM_HPP | |
| 11 | #define BOOST_HANA_TRANSFORM_HPP | |
| 12 | ||
| 13 | #include <boost/hana/fwd/transform.hpp> | |
| 14 | ||
| 15 | #include <boost/hana/bool.hpp> | |
| 16 | #include <boost/hana/concept/functor.hpp> | |
| 17 | #include <boost/hana/concept/sequence.hpp> | |
| 18 | #include <boost/hana/config.hpp> | |
| 19 | #include <boost/hana/core/dispatch.hpp> | |
| 20 | #include <boost/hana/core/make.hpp> | |
| 21 | #include <boost/hana/functional/always.hpp> | |
| 22 | #include <boost/hana/fwd/adjust_if.hpp> | |
| 23 | #include <boost/hana/unpack.hpp> | |
| 24 | ||
| 25 | ||
| 26 | BOOST_HANA_NAMESPACE_BEGIN | |
| 27 | //! @cond | |
| 28 | template <typename Xs, typename F> | |
| 29 | constexpr auto transform_t::operator()(Xs&& xs, F&& f) const { | |
| 30 | using S = typename hana::tag_of<Xs>::type; | |
| 31 | using Transform = BOOST_HANA_DISPATCH_IF(transform_impl<S>, | |
| 32 | hana::Functor<S>::value | |
| 33 | ); | |
| 34 | ||
| 35 | #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS | |
| 36 | static_assert(hana::Functor<S>::value, | |
| 37 | "hana::transform(xs, f) requires 'xs' to be a Functor"); | |
| 38 | #endif | |
| 39 | ||
| 40 | return Transform::apply(static_cast<Xs&&>(xs), static_cast<F&&>(f)); | |
| 41 | } | |
| 42 | //! @endcond | |
| 43 | ||
| 44 | template <typename Fun, bool condition> | |
| 45 | struct transform_impl<Fun, when<condition>> : default_ { | |
| 46 | template <typename Xs, typename F> | |
| 47 | static constexpr auto apply(Xs&& xs, F&& f) { | |
| 48 | return hana::adjust_if(static_cast<Xs&&>(xs), | |
| 49 | hana::always(hana::true_c), | |
| 50 | static_cast<F&&>(f)); | |
| 51 | } | |
| 52 | }; | |
| 53 | ||
| 54 | template <typename S> | |
| 55 | struct transform_impl<S, when<Sequence<S>::value>> { | |
| 56 | //! @cond | |
| 57 | template <typename F> | |
| 58 | struct transformer { | |
| 59 | F f; | |
| 60 | template <typename ...Xs> | |
| 61 | constexpr auto operator()(Xs&& ...xs) const { | |
| 62 | return hana::make<S>((*f)(static_cast<Xs&&>(xs))...); | |
| 63 | } | |
| 64 | }; | |
| 65 | //! @endcond | |
| 66 | ||
| 67 | template <typename Xs, typename F> | |
| 68 | static constexpr auto apply(Xs&& xs, F&& f) { | |
| 69 | // We use a pointer to workaround a Clang 3.5 ICE | |
| 70 | return hana::unpack(static_cast<Xs&&>(xs), | |
| 71 | transformer<decltype(&f)>{&f}); | |
| 72 | } | |
| 73 | }; | |
| 74 | BOOST_HANA_NAMESPACE_END | |
| 75 | ||
| 76 | #endif // !BOOST_HANA_TRANSFORM_HPP |