/// \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_RANGE_FWD_HPP
#define RANGES_V3_RANGE_FWD_HPP

#include <type_traits>
#include <utility>

#include <meta/meta.hpp>

#include <concepts/concepts.hpp>
#include <concepts/compare.hpp>

#include <range/v3/detail/config.hpp>
#include <range/v3/utility/static_const.hpp>
#include <range/v3/version.hpp>

/// \defgroup group-iterator Iterator
/// Iterator functionality

/// \defgroup group-iterator-concepts Iterator Concepts
/// \ingroup group-iterator
/// Iterator concepts

/// \defgroup group-range Range
/// Core range functionality

/// \defgroup group-range-concepts Range Concepts
/// \ingroup group-range
/// Range concepts

/// \defgroup group-algorithms Algorithms
/// Iterator- and range-based algorithms, like the standard algorithms

/// \defgroup group-views Views
/// Lazy, non-owning, non-mutating, composable range views

/// \defgroup group-actions Actions
/// Eager, mutating, composable algorithms

/// \defgroup group-utility Utility
/// Utility classes

/// \defgroup group-functional Functional
/// Function and function object utilities

/// \defgroup group-numerics Numerics
/// Numeric utilities

#include <range/v3/detail/prologue.hpp>

RANGES_DIAGNOSTIC_PUSH
RANGES_DIAGNOSTIC_IGNORE_CXX17_COMPAT

namespace ranges
{
    /// \cond
    namespace views
    {
    }

    namespace actions
    {
    }

// GCC either fails to accept an attribute on a namespace, or else
// it ignores the deprecation attribute. Frustrating.
#if(RANGES_CXX_VER < RANGES_CXX_STD_17 || defined(__GNUC__) && !defined(__clang__))
    inline namespace v3
    {
        using namespace ranges;
    }

    namespace view = views;
    namespace action = actions;
#else
    inline namespace RANGES_DEPRECATED(
        "The name ranges::v3 namespace is deprecated. "
        "Please discontinue using it.") v3
    {
        using namespace ranges;
    }

    namespace RANGES_DEPRECATED(
        "The ranges::view namespace has been renamed to ranges::views. "
        "(Sorry!)") view
    {
        using namespace views;
    }

    namespace RANGES_DEPRECATED(
        "The ranges::action namespace has been renamed to ranges::actions. "
        "(Sorry!)") action
    {
        using namespace actions;
    }
#endif

    namespace _end_
    {
        struct fn;
    }
    using end_fn = _end_::fn;

    namespace _size_
    {
        struct fn;
    }

    template<typename>
    struct result_of;

    template<typename Sig>
    using result_of_t RANGES_DEPRECATED(
        "ranges::result_of_t is deprecated. "
        "Please use ranges::invoke_result_t") = meta::_t<result_of<Sig>>;
    /// \endcond

    template<typename...>
    struct variant;

    struct dangling;

    struct make_pipeable_fn;

    struct pipeable_base;

    template<typename First, typename Second>
    struct composed;

    template<typename... Fns>
    struct overloaded;

    namespace actions
    {
        template<typename ActionFn>
        struct action_closure;
    }

    namespace views
    {
        template<typename ViewFn>
        struct view_closure;
    }

    struct advance_fn;

    struct advance_to_fn;

    struct advance_bounded_fn;

    struct next_fn;

    struct prev_fn;

    struct distance_fn;

    struct iter_size_fn;

    template<typename T>
    struct indirectly_readable_traits;

    template<typename T>
    using readable_traits RANGES_DEPRECATED("Please use ranges::indirectly_readable_traits")
     = indirectly_readable_traits<T>;

    template<typename T>
    struct incrementable_traits;

    struct view_base
    {};

    /// \cond
    namespace detail
    {
        template<typename T>
        struct difference_type_;

        template<typename T>
        struct value_type_;
    } // namespace detail

    template<typename T>
    using difference_type RANGES_DEPRECATED(
        "ranges::difference_type<T>::type is deprecated. Use "
        "ranges::incrementable_traits<T>::difference_type instead.") =
        detail::difference_type_<T>;

    template<typename T>
    using value_type RANGES_DEPRECATED(
        "ranges::value_type<T>::type is deprecated. Use "
        "ranges::indirectly_readable_traits<T>::value_type instead.") = detail::value_type_<T>;

    template<typename T>
    struct size_type;
    /// \endcond

    /// \cond
    namespace detail
    {
        struct ignore_t
        {
            ignore_t() = default;
            template<typename T>
            constexpr ignore_t(T &&) noexcept
            {}
            template<typename T>
            constexpr ignore_t const & operator=(T &&) const noexcept
            {
                return *this;
            }
        };

        struct value_init
        {
            template<typename T>
            operator T() const
            {
                return T{};
            }
        };

        struct make_compressed_pair_fn;

        template<typename T>
        constexpr meta::_t<std::remove_reference<T>> && move(T && t) noexcept
        {
            return static_cast<meta::_t<std::remove_reference<T>> &&>(t);
        }

        struct as_const_fn
        {
            template<typename T>
            constexpr T const & operator()(T & t) const noexcept
            {
                return t;
            }
            template<typename T>
            constexpr T const && operator()(T && t) const noexcept
            {
                return (T &&) t;
            }
        };

        RANGES_INLINE_VARIABLE(as_const_fn, as_const)

        template<typename T>
        using as_const_t = decltype(as_const(std::declval<T>()));

        template<typename T>
        using decay_t = meta::_t<std::decay<T>>;

        template<typename T, typename R = meta::_t<std::remove_reference<T>>>
        using as_ref_t =
            meta::_t<std::add_lvalue_reference<meta::_t<std::remove_const<R>>>>;

        template<typename T, typename R = meta::_t<std::remove_reference<T>>>
        using as_cref_t = meta::_t<std::add_lvalue_reference<R const>>;

        struct get_first;
        struct get_second;

        template<typename Val1, typename Val2>
        struct replacer_fn;

        template<typename Pred, typename Val>
        struct replacer_if_fn;

        template<typename I>
        struct move_into_cursor;

        template<typename Int>
        struct from_end_;

        template<typename... Ts>
        constexpr int ignore_unused(Ts &&...)
        {
            return 42;
        }

        template<int I>
        struct priority_tag : priority_tag<I - 1>
        {};

        template<>
        struct priority_tag<0>
        {};

#if defined(__clang__) && !defined(_LIBCPP_VERSION)
        template<typename T, typename... Args>
        RANGES_INLINE_VAR constexpr bool is_trivially_constructible_v =
            __is_trivially_constructible(T, Args...);
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivially_default_constructible_v =
            is_trivially_constructible_v<T>;
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivially_copy_constructible_v =
            is_trivially_constructible_v<T, T const &>;
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivially_move_constructible_v =
            is_trivially_constructible_v<T, T>;
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivially_copyable_v =
            __is_trivially_copyable(T);
        template<typename T, typename U>
        RANGES_INLINE_VAR constexpr bool is_trivially_assignable_v =
            __is_trivially_assignable(T, U);
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivially_copy_assignable_v =
            is_trivially_assignable_v<T &, T const &>;
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivially_move_assignable_v =
            is_trivially_assignable_v<T &, T>;

        template<typename T, typename... Args>
        struct is_trivially_constructible
          : meta::bool_<is_trivially_constructible_v<T, Args...>>
        {};
        template<typename T>
        struct is_trivially_default_constructible
          : meta::bool_<is_trivially_default_constructible_v<T>>
        {};
        template<typename T>
        struct is_trivially_copy_constructible
          : meta::bool_<is_trivially_copy_constructible_v<T>>
        {};
        template<typename T>
        struct is_trivially_move_constructible
          : meta::bool_<is_trivially_move_constructible_v<T>>
        {};
        template<typename T>
        struct is_trivially_copyable
          : meta::bool_<is_trivially_copyable_v<T>>
        {};
        template<typename T, typename U>
        struct is_trivially_assignable
          : meta::bool_<is_trivially_assignable_v<T, U>>
        {};
        template<typename T>
        struct is_trivially_copy_assignable
          : meta::bool_<is_trivially_copy_assignable_v<T>>
        {};
        template<typename T>
        struct is_trivially_move_assignable
          : meta::bool_<is_trivially_move_assignable_v<T>>
        {};
#else
        using std::is_trivially_constructible;
        using std::is_trivially_default_constructible;
        using std::is_trivially_copy_assignable;
        using std::is_trivially_copy_constructible;
        using std::is_trivially_copyable;
        using std::is_trivially_assignable;
        using std::is_trivially_move_assignable;
        using std::is_trivially_move_constructible;
#if META_CXX_TRAIT_VARIABLE_TEMPLATES
        using std::is_trivially_constructible_v;
        using std::is_trivially_default_constructible_v;
        using std::is_trivially_copy_assignable_v;
        using std::is_trivially_copy_constructible_v;
        using std::is_trivially_copyable_v;
        using std::is_trivially_assignable_v;
        using std::is_trivially_move_assignable_v;
        using std::is_trivially_move_constructible_v;
#else
        template<typename T, typename... Args>
        RANGES_INLINE_VAR constexpr bool is_trivially_constructible_v =
            is_trivially_constructible<T, Args...>::value;
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivially_default_constructible_v =
            is_trivially_default_constructible<T>::value;
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivially_copy_constructible_v =
            is_trivially_copy_constructible<T>::value;
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivially_move_constructible_v =
            is_trivially_move_constructible<T>::value;
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivially_copyable_v =
            is_trivially_copyable<T>::value;
        template<typename T, typename U>
        RANGES_INLINE_VAR constexpr bool is_trivially_assignable_v =
            is_trivially_assignable<T, U>::value;
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivially_copy_assignable_v =
            is_trivially_copy_assignable<T>::value;
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivially_move_assignable_v =
            is_trivially_move_assignable<T>::value;
#endif
#endif

        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_trivial_v =
            is_trivially_copyable_v<T> &&
            is_trivially_default_constructible_v<T>;

        template<typename T>
        struct is_trivial
          : meta::bool_<is_trivial_v<T>>
        {};

#if RANGES_CXX_LIB_IS_FINAL > 0
#if defined(__clang__) && !defined(_LIBCPP_VERSION)
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_final_v = __is_final(T);

        template<typename T>
        struct is_final
          : meta::bool_<is_final_v<T>>
        {};
#else
        using std::is_final;
#if META_CXX_TRAIT_VARIABLE_TEMPLATES
        using std::is_final_v;
#else
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_final_v = is_final<T>::value;
#endif
#endif
#else
        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_final_v = false;

        template<typename T>
        using is_final = std::false_type;
#endif

        // Work around libc++'s buggy std::is_function
        // Function types here:
        template<typename T>
        char (&is_function_impl_(priority_tag<0>))[1];

        // Array types here:
        template<typename T, typename = decltype((*(T *)0)[0])>
        char (&is_function_impl_(priority_tag<1>))[2];

        // Anything that can be returned from a function here (including
        // void and reference types):
        template<typename T, typename = T (*)()>
        char (&is_function_impl_(priority_tag<2>))[3];

        // Classes and unions (including abstract types) here:
        template<typename T, typename = int T::*>
        char (&is_function_impl_(priority_tag<3>))[4];

        template<typename T>
        RANGES_INLINE_VAR constexpr bool is_function_v =
            sizeof(detail::is_function_impl_<T>(priority_tag<3>{})) == 1;

        template<typename T>
        struct remove_rvalue_reference
        {
            using type = T;
        };

        template<typename T>
        struct remove_rvalue_reference<T &&>
        {
            using type = T;
        };

        template<typename T>
        using remove_rvalue_reference_t = meta::_t<remove_rvalue_reference<T>>;

        // Workaround bug in the Standard Library:
        // From cannot be an incomplete class type despite that
        // is_convertible<X, Y> should be equivalent to is_convertible<X&&, Y>
        // in such a case.
        template<typename From, typename To>
        using is_convertible =
            std::is_convertible<meta::_t<std::add_rvalue_reference<From>>, To>;
    } // namespace detail
    /// \endcond

    struct begin_tag
    {};
    struct end_tag
    {};
    struct copy_tag
    {};
    struct move_tag
    {};

    template<typename T>
    using uncvref_t = meta::_t<std::remove_cv<meta::_t<std::remove_reference<T>>>>;

    struct not_equal_to;
    struct equal_to;
    struct less;
#if __cplusplus > 201703L && __has_include(<compare>) && \
    defined(__cpp_concepts) && defined(__cpp_impl_three_way_comparison)
    struct compare_three_way;
#endif // __cplusplus
    struct identity;
    template<typename Pred>
    struct logical_negate;

    enum cardinality : std::ptrdiff_t
    {
        infinite = -3,
        unknown = -2,
        finite = -1
    };

    template<typename Rng, typename Void = void>
    struct range_cardinality;

    template<typename Rng>
    using is_finite = meta::bool_<range_cardinality<Rng>::value >= finite>;

    template<typename Rng>
    using is_infinite = meta::bool_<range_cardinality<Rng>::value == infinite>;

    template<typename S, typename I>
    RANGES_INLINE_VAR constexpr bool disable_sized_sentinel = false;

    template<typename R>
    RANGES_INLINE_VAR constexpr bool enable_borrowed_range = false;

    namespace detail
    {
        template<typename R>
        RANGES_DEPRECATED("Please use ranges::enable_borrowed_range instead.")
        RANGES_INLINE_VAR constexpr bool enable_safe_range = enable_borrowed_range<R>;
    } // namespace detail

    using detail::enable_safe_range;

    template<typename Cur>
    struct basic_mixin;

    template<typename Cur>
    struct RANGES_EMPTY_BASES basic_iterator;

    template<cardinality>
    struct basic_view : view_base
    {};

    template<typename Derived, cardinality C = finite>
    struct view_facade;

    template<typename Derived, typename BaseRng,
             cardinality C = range_cardinality<BaseRng>::value>
    struct view_adaptor;

    template<typename I, typename S>
    struct common_iterator;

    /// \cond
    namespace detail
    {
        template<typename I>
        struct cpp17_iterator_cursor;

        template<typename I>
        using cpp17_iterator = basic_iterator<cpp17_iterator_cursor<I>>;
    } // namespace detail
    /// \endcond

    template<typename First, typename Second>
    struct compressed_pair;

    template<typename T>
    struct bind_element;

    template<typename T>
    using bind_element_t = meta::_t<bind_element<T>>;

    template<typename Derived, cardinality = finite>
    struct view_interface;

    template<typename T>
    struct istream_view;

    template<typename I, typename S = I>
    struct RANGES_EMPTY_BASES iterator_range;

    template<typename I, typename S = I>
    struct sized_iterator_range;

    template<typename T>
    struct reference_wrapper;

    // Views
    //
    template<typename Rng, typename Pred>
    struct RANGES_EMPTY_BASES adjacent_filter_view;

    namespace views
    {
        struct adjacent_filter_fn;
    }

    template<typename Rng, typename Pred>
    struct RANGES_EMPTY_BASES adjacent_remove_if_view;

    namespace views
    {
        struct adjacent_remove_if_fn;
    }

    namespace views
    {
        struct all_fn;
    }


    template<typename Rng, typename Fun>
    struct chunk_by_view;

    namespace views
    {
        struct chunk_by_fn;
    }

    template<typename Rng>
    struct const_view;

    namespace views
    {
        struct const_fn;
    }

    template<typename I>
    struct counted_view;

    namespace views
    {
        struct counted_fn;
    }

    struct default_sentinel_t;

    template<typename I>
    struct move_iterator;

    template<typename I>
    using move_into_iterator = basic_iterator<detail::move_into_cursor<I>>;

    template<typename Rng, bool = (bool)is_infinite<Rng>()>
    struct RANGES_EMPTY_BASES cycled_view;

    namespace views
    {
        struct cycle_fn;
    }

    /// \cond
    namespace detail
    {
        template<typename I>
        struct reverse_cursor;
    }
    /// \endcond

    template<typename I>
    using reverse_iterator = basic_iterator<detail::reverse_cursor<I>>;

    template<typename T>
    struct empty_view;

    namespace views
    {
        struct empty_fn;
    }

    template<typename Rng, typename Fun>
    struct group_by_view;

    namespace views
    {
        struct group_by_fn;
    }

    template<typename Rng>
    struct indirect_view;

    namespace views
    {
        struct indirect_fn;
    }

    struct unreachable_sentinel_t;

    template<typename From, typename To = unreachable_sentinel_t>
    struct iota_view;

    template<typename From, typename To = From>
    struct closed_iota_view;

    namespace views
    {
        struct iota_fn;
        struct closed_iota_fn;
    } // namespace views

    template<typename Rng>
    struct join_view;

    template<typename Rng, typename ValRng>
    struct join_with_view;

    namespace views
    {
        struct join_fn;
    }

    template<typename... Rngs>
    struct concat_view;

    namespace views
    {
        struct concat_fn;
    }

    template<typename Rng, typename Fun>
    struct partial_sum_view;

    namespace views
    {
        struct partial_sum_fn;
    }

    template<typename Rng>
    struct move_view;

    namespace views
    {
        struct move_fn;
    }

    template<typename Rng>
    struct ref_view;

    namespace views
    {
        struct ref_fn;
    }

    template<typename Val>
    struct repeat_view;

    namespace views
    {
        struct repeat_fn;
    }

    template<typename Rng>
    struct RANGES_EMPTY_BASES reverse_view;

    namespace views
    {
        struct reverse_fn;
    }

    template<typename Rng>
    struct slice_view;

    namespace views
    {
        struct slice_fn;
    }

    // template<typename Rng, typename Fun>
    // struct split_view;

    // namespace views
    // {
    //     struct split_fn;
    // }

    template<typename Rng>
    struct single_view;

    namespace views
    {
        struct single_fn;
    }

    template<typename Rng>
    struct stride_view;

    namespace views
    {
        struct stride_fn;
    }

    template<typename Rng>
    struct take_view;

    namespace views
    {
        struct take_fn;
    }

    /// \cond
    namespace detail
    {
        template<typename Rng>
        struct is_random_access_common_;

        template<typename Rng,
                 bool IsRandomAccessCommon = is_random_access_common_<Rng>::value>
        struct take_exactly_view_;
    } // namespace detail
    /// \endcond

    template<typename Rng>
    using take_exactly_view = detail::take_exactly_view_<Rng>;

    namespace views
    {
        struct take_exactly_fn;
    }

    template<typename Rng, typename Pred>
    struct iter_take_while_view;

    template<typename Rng, typename Pred>
    struct take_while_view;

    namespace views
    {
        struct iter_take_while_fn;
        struct take_while_fn;
    } // namespace views

    template<typename Rng, typename Regex, typename SubMatchRange>
    struct tokenize_view;

    namespace views
    {
        struct tokenize_fn;
    }

    template<typename Rng, typename Fun>
    struct iter_transform_view;

    template<typename Rng, typename Fun>
    struct transform_view;

    namespace views
    {
        struct transform_fn;
    }

    template<typename Rng, typename Val1, typename Val2>
    using replace_view = iter_transform_view<Rng, detail::replacer_fn<Val1, Val2>>;

    template<typename Rng, typename Pred, typename Val>
    using replace_if_view = iter_transform_view<Rng, detail::replacer_if_fn<Pred, Val>>;

    namespace views
    {
        struct replace_fn;

        struct replace_if_fn;
    } // namespace views

    template<typename Rng, typename Pred>
    struct trim_view;

    namespace views
    {
        struct trim_fn;
    }

    template<typename I>
    struct unbounded_view;

    namespace views
    {
        struct unbounded_fn;
    }

    template<typename Rng>
    using unique_view = adjacent_filter_view<Rng, logical_negate<equal_to>>;

    namespace views
    {
        struct unique_fn;
    }

    template<typename Rng>
    using keys_range_view = transform_view<Rng, detail::get_first>;

    template<typename Rng>
    using values_view = transform_view<Rng, detail::get_second>;

    namespace views
    {
        struct keys_fn;

        struct values_fn;
    } // namespace views

    template<typename Fun, typename... Rngs>
    struct iter_zip_with_view;

    template<typename Fun, typename... Rngs>
    struct zip_with_view;

    template<typename... Rngs>
    struct zip_view;

    namespace views
    {
        struct iter_zip_with_fn;

        struct zip_with_fn;

        struct zip_fn;
    } // namespace views
} // namespace ranges

/// \cond
namespace ranges
{
    namespace concepts = ::concepts;
    using namespace ::concepts::defs;
    using ::concepts::and_v;
} // namespace ranges
/// \endcond

RANGES_DIAGNOSTIC_POP

#include <range/v3/detail/epilogue.hpp>

#endif