1 /*! 2 @file 3 Defines `boost::hana::remove_if`. 4 5 @copyright Louis Dionne 2013-2017 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_REMOVE_IF_HPP 11 #define BOOST_HANA_REMOVE_IF_HPP 12 13 #include <boost/hana/fwd/remove_if.hpp> 14 15 #include <boost/hana/concept/monad_plus.hpp> 16 #include <boost/hana/config.hpp> 17 #include <boost/hana/core/dispatch.hpp> 18 #include <boost/hana/filter.hpp> 19 #include <boost/hana/functional/compose.hpp> 20 #include <boost/hana/not.hpp> 21 22 23 BOOST_HANA_NAMESPACE_BEGIN 24 //! @cond 25 template <typename Xs, typename Pred> operator ()(Xs && xs,Pred && pred) const26 constexpr auto remove_if_t::operator()(Xs&& xs, Pred&& pred) const { 27 using M = typename hana::tag_of<Xs>::type; 28 using RemoveIf = BOOST_HANA_DISPATCH_IF(remove_if_impl<M>, 29 hana::MonadPlus<M>::value 30 ); 31 32 #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS 33 static_assert(hana::MonadPlus<M>::value, 34 "hana::remove_if(xs, predicate) requires 'xs' to be a MonadPlus"); 35 #endif 36 37 return RemoveIf::apply(static_cast<Xs&&>(xs), 38 static_cast<Pred&&>(pred)); 39 } 40 //! @endcond 41 42 template <typename M, bool condition> 43 struct remove_if_impl<M, when<condition>> : default_ { 44 template <typename Xs, typename Pred> applyremove_if_impl45 static constexpr auto apply(Xs&& xs, Pred&& pred) { 46 return hana::filter(static_cast<Xs&&>(xs), 47 hana::compose(hana::not_, static_cast<Pred&&>(pred))); 48 } 49 }; 50 BOOST_HANA_NAMESPACE_END 51 52 #endif // !BOOST_HANA_REMOVE_IF_HPP 53