text: /// \file
  // Range v3 library
  //
  //  Copyright Andrey Diduh 2019
  //
  //  Use, modification and distribution is subject to the
  //  Boost Software License, Version 1.0. (See accompanying
  //  file LICENSE_1_0.txt or copy at
  //  http://www.boost.org/LICENSE_1_0.txt)
  //
  // Project home: https://github.com/ericniebler/range-v3
  //
  #ifndef RANGES_V3_ACTION_UNSTABLE_REMOVE_IF_HPP
  #define RANGES_V3_ACTION_UNSTABLE_REMOVE_IF_HPP
  
  #include <functional>
  #include <utility>
  
  #include <concepts/concepts.hpp>
  
  #include <range/v3/range_fwd.hpp>
  
  #include <range/v3/action/action.hpp>
  #include <range/v3/action/erase.hpp>
  #include <range/v3/algorithm/unstable_remove_if.hpp>
  #include <range/v3/functional/bind.hpp>
  #include <range/v3/functional/identity.hpp>
  #include <range/v3/iterator/concepts.hpp>
  #include <range/v3/range/access.hpp>
  #include <range/v3/range/concepts.hpp>
  
  namespace ranges
  {
      /// \addtogroup group-actions
      /// @{
      namespace action
      {
          struct unstable_remove_if_fn
          {
          private:
              friend action_access;
              template<typename C, typename P = identity>
              static auto CPP_fun(bind)(unstable_remove_if_fn unstable_remove_if, C pred,
                                        P proj = P{})(requires(!Range<C>))
              {
                  return std::bind(unstable_remove_if,
                                   std::placeholders::_1,
                                   protect(std::move(pred)),
                                   protect(std::move(proj)));
              }
  
          public:
              template<typename Rng, typename C, typename P = identity>
              auto operator()(Rng && rng, C pred, P proj = P{}) const -> CPP_ret(Rng)( //
                  requires BidirectionalRange<Rng> && CommonRange<Rng> &&
                      Permutable<iterator_t<Rng>> &&
                          IndirectUnaryPredicate<C, projected<iterator_t<Rng>, P>> &&
                              ErasableRange<Rng, iterator_t<Rng>, iterator_t<Rng>>)
              {
                  auto it = ranges::unstable_remove_if(ranges::begin(rng),
                                                       ranges::end(rng),
                                                       std::move(pred),
                                                       std::move(proj));
                  ranges::erase(rng, it, ranges::end(rng));
                  return static_cast<Rng &&>(rng);
              }
          };
  
          /// \ingroup group-actions
          /// \sa `action`
          /// \sa `action::unstable_remove_if_fn`
          RANGES_INLINE_VARIABLE(action<unstable_remove_if_fn>, unstable_remove_if)
      } // namespace action
      /// @}
  } // namespace ranges
  
  #endif // RANGES_V3_ACTION_UNSTABLE_REMOVE_IF_HPP
  