text: /// \file
  // Range v3 library
  //
  //  Copyright Eric Niebler 2013-present
  //
  //  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_VIEW_DELIMIT_HPP
  #define RANGES_V3_VIEW_DELIMIT_HPP
  
  #include <meta/meta.hpp>
  
  #include <range/v3/range_fwd.hpp>
  
  #include <range/v3/functional/bind_back.hpp>
  #include <range/v3/iterator/concepts.hpp>
  #include <range/v3/iterator/unreachable_sentinel.hpp>
  #include <range/v3/range/concepts.hpp>
  #include <range/v3/utility/static_const.hpp>
  #include <range/v3/view/adaptor.hpp>
  #include <range/v3/view/all.hpp>
  #include <range/v3/view/subrange.hpp>
  #include <range/v3/view/view.hpp>
  
  namespace ranges
  {
      /// \addtogroup group-views
      /// @{
      template<typename Rng, typename Val>
      struct delimit_view
        : view_adaptor<delimit_view<Rng, Val>, Rng,
                       is_finite<Rng>::value ? finite : unknown>
      {
      private:
          friend range_access;
          Val value_;
  
          struct sentinel_adaptor : adaptor_base
          {
              sentinel_adaptor() = default;
              sentinel_adaptor(Val value)
                : value_(std::move(value))
              {}
              template<class I, class S>
              bool empty(I const & it, S const & end) const
              {
                  return it == end || *it == value_;
              }
              Val value_;
          };
  
          sentinel_adaptor end_adaptor() const
          {
              return {value_};
          }
  
      public:
          delimit_view() = default;
          constexpr delimit_view(Rng rng, Val value)
            : delimit_view::view_adaptor{std::move(rng)}
            , value_(std::move(value))
          {}
      };
  
  #if RANGES_CXX_DEDUCTION_GUIDES >= RANGES_CXX_DEDUCTION_GUIDES_17
      CPP_template(typename Rng, typename Val)(requires copy_constructible<Val>)
          delimit_view(Rng &&, Val)
              ->delimit_view<views::all_t<Rng>, Val>;
  #endif
  
      namespace views
      {
          struct delimit_impl_fn
          {
          private:
              friend view_access;
              template<typename Val>
              static constexpr auto bind(delimit_impl_fn delimit, Val value)
              {
                  return make_pipeable(bind_back(delimit, std::move(value)));
              }
  
          public:
              template<typename Rng, typename Val>
              constexpr auto operator()(Rng && rng, Val value) const
                  -> CPP_ret(delimit_view<all_t<Rng>, Val>)( //
                      requires viewable_range<Rng> && input_range<Rng> && semiregular<Val> &&
                          equality_comparable_with<Val, range_reference_t<Rng>>)
              {
                  return {all(static_cast<Rng &&>(rng)), std::move(value)};
              }
          };
  
          struct delimit_fn : view<delimit_impl_fn>
          {
              using view<delimit_impl_fn>::operator();
  
              template<typename I_, typename Val, typename I = detail::decay_t<I_>>
              constexpr auto operator()(I_ && begin_, Val value) const
                  -> CPP_ret(delimit_view<subrange<I, unreachable_sentinel_t>, Val>)( //
                      requires(!range<I_> && convertible_to<I_, I> && input_iterator<I> &&
                               semiregular<Val> &&
                               equality_comparable_with<Val, iter_reference_t<I>>))
              {
                  return {{static_cast<I_ &&>(begin_), {}}, std::move(value)};
              }
          };
  
          /// \relates delimit_fn
          /// \ingroup group-views
          RANGES_INLINE_VARIABLE(delimit_fn, delimit)
      } // namespace views
      /// @}
  } // namespace ranges
  
  #include <range/v3/detail/satisfy_boost_range.hpp>
  RANGES_SATISFY_BOOST_RANGE(::ranges::delimit_view)
  
  #endif
  