text: /// \file
  // Range v3 library
  //
  //  Copyright Eric Niebler 2014
  //
  //  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_ALGORITHM_REPLACE_COPY_HPP
  #define RANGES_V3_ALGORITHM_REPLACE_COPY_HPP
  
  #include <range/v3/range_fwd.hpp>
  #include <range/v3/begin_end.hpp>
  #include <range/v3/range_concepts.hpp>
  #include <range/v3/range_traits.hpp>
  #include <range/v3/utility/iterator_concepts.hpp>
  #include <range/v3/utility/iterator_traits.hpp>
  #include <range/v3/utility/functional.hpp>
  #include <range/v3/utility/invokable.hpp>
  
  namespace ranges
  {
      inline namespace v3
      {
          /// \ingroup group-concepts
          template<typename I, typename O, typename T0, typename T1, typename P = ident,
              typename V = iterator_common_reference_t<I>,
              typename X = concepts::Invokable::result_t<P, V>>
          using ReplaceCopyable = meta::fast_and<
              InputIterator<I>,
              WeakOutputIterator<O, T1>,
              IndirectlyCopyable<I, O>,
              Invokable<P, V>,
              EqualityComparable<X, T0>>;
  
          /// \addtogroup group-algorithms
          /// @{
          struct replace_copy_fn
          {
              template<typename I, typename S, typename O, typename T0, typename T1, typename P = ident,
                  CONCEPT_REQUIRES_(ReplaceCopyable<I, O, T0, T1, P>() && IteratorRange<I, S>())>
              std::pair<I, O> operator()(I begin, S end, O out, T0 const & old_value, T1 const & new_value, P proj_ = {}) const
              {
                  auto &&proj = invokable(proj_);
                  for(; begin != end; ++begin, ++out)
                      if(proj(*begin) == old_value)
                          *out = new_value;
                      else
                          *out = *begin;
                  return {begin, out};
              }
  
              template<typename Rng, typename O, typename T0, typename T1, typename P = ident,
                  typename I = range_iterator_t<Rng>,
                  CONCEPT_REQUIRES_(ReplaceCopyable<I, O, T0, T1, P>() && Iterable<Rng &>())>
              std::pair<I, O> operator()(Rng & rng, O out, T0 const & old_value, T1 const & new_value, P proj = {}) const
              {
                  return (*this)(begin(rng), end(rng), std::move(out), old_value, new_value, std::move(proj));
              }
          };
  
          /// \sa `replace_copy_fn`
          /// \ingroup group-algorithms
          constexpr replace_copy_fn replace_copy{};
  
          /// @}
      } // namespace v3
  } // namespace ranges
  
  #endif // include guard
  