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concepts.hpp
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concepts.hpp
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/// \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_ITERATOR_CONCEPTS_HPP
#define RANGES_V3_ITERATOR_CONCEPTS_HPP
#include <iterator>
#include <type_traits>
#include <meta/meta.hpp>
#include <concepts/concepts.hpp>
#include <range/v3/range_fwd.hpp>
#include <range/v3/functional/comparisons.hpp>
#include <range/v3/functional/concepts.hpp>
#include <range/v3/functional/identity.hpp>
#include <range/v3/functional/invoke.hpp>
#include <range/v3/iterator/access.hpp>
#include <range/v3/iterator/traits.hpp>
#ifdef _GLIBCXX_DEBUG
#include <debug/safe_iterator.h>
#endif
#include <range/v3/detail/disable_warnings.hpp>
namespace ranges
{
/// \addtogroup group-iterator-concepts
/// @{
/// \cond
namespace detail
{
template<typename I>
using iter_traits_t = if_then_t<is_std_iterator_traits_specialized_v<I>,
std::iterator_traits<I>, I>;
#if defined(_GLIBCXX_DEBUG)
template<typename I, typename T, typename Seq>
auto iter_concept_(__gnu_debug::_Safe_iterator<T *, Seq>, priority_tag<3>)
-> CPP_ret(ranges::contiguous_iterator_tag)( //
requires same_as<I, __gnu_debug::_Safe_iterator<T *, Seq>>);
#endif
#if defined(__GLIBCXX__)
template<typename I, typename T, typename Seq>
auto iter_concept_(__gnu_cxx::__normal_iterator<T *, Seq>, priority_tag<3>)
-> CPP_ret(ranges::contiguous_iterator_tag)( //
requires same_as<I, __gnu_cxx::__normal_iterator<T *, Seq>>);
#endif
#if defined(_LIBCPP_VERSION)
template<typename I, typename T>
auto iter_concept_(std::__wrap_iter<T *>, priority_tag<3>)
-> CPP_ret(ranges::contiguous_iterator_tag)( //
requires same_as<I, std::__wrap_iter<T *>>);
#endif
#if defined(_MSVC_STL_VERSION)
template<typename I>
auto iter_concept_(I, priority_tag<3>)
-> CPP_ret(ranges::contiguous_iterator_tag)( //
requires same_as<I, class I::_Array_iterator>);
template<typename I>
auto iter_concept_(I, priority_tag<3>)
-> CPP_ret(ranges::contiguous_iterator_tag)( //
requires same_as<I, class I::_Array_const_iterator>);
template<typename I>
auto iter_concept_(I, priority_tag<3>)
-> CPP_ret(ranges::contiguous_iterator_tag)( //
requires same_as<I, class I::_Vector_iterator>);
template<typename I>
auto iter_concept_(I, priority_tag<3>)
-> CPP_ret(ranges::contiguous_iterator_tag)( //
requires same_as<I, class I::_Vector_const_iterator>);
template<typename I>
auto iter_concept_(I, priority_tag<3>)
-> CPP_ret(ranges::contiguous_iterator_tag)( //
requires same_as<I, class I::_String_iterator>);
template<typename I>
auto iter_concept_(I, priority_tag<3>)
-> CPP_ret(ranges::contiguous_iterator_tag)( //
requires same_as<I, class I::_String_const_iterator>);
template<typename I>
auto iter_concept_(I, priority_tag<3>)
-> CPP_ret(ranges::contiguous_iterator_tag)( //
requires same_as<I, class I::_String_view_iterator>);
#endif
template<typename I, typename T>
auto iter_concept_(T *, priority_tag<3>)
-> CPP_ret(ranges::contiguous_iterator_tag)( //
requires same_as<I, T *>);
template<typename I>
auto iter_concept_(I, priority_tag<2>) ->
typename iter_traits_t<I>::iterator_concept;
template<typename I>
auto iter_concept_(I, priority_tag<1>) ->
typename iter_traits_t<I>::iterator_category;
template<typename I>
auto iter_concept_(I, priority_tag<0>)
-> enable_if_t<!is_std_iterator_traits_specialized_v<I>,
std::random_access_iterator_tag>;
template<typename I>
using iter_concept_t =
decltype(iter_concept_<I>(std::declval<I>(), priority_tag<3>{}));
using ::concepts::detail::weakly_equality_comparable_with_;
template<typename I>
using readable_types_t =
meta::list<iter_value_t<I>, iter_reference_t<I>, iter_rvalue_reference_t<I>>;
} // namespace detail
/// \endcond
// clang-format off
template<typename I>
CPP_concept_fragment(readable_,
requires (/*I const i*/) //
(
// { *i } -> same_as<iter_reference_t<I>>;
// { iter_move(i) } -> same_as<iter_rvalue_reference_t<I>>;
0
) &&
same_as<iter_reference_t<I const>, iter_reference_t<I>> &&
same_as<iter_rvalue_reference_t<I const>, iter_rvalue_reference_t<I>> &&
common_reference_with<iter_reference_t<I> &&, iter_value_t<I> &> &&
common_reference_with<iter_reference_t<I> &&,
iter_rvalue_reference_t<I> &&> &&
common_reference_with<iter_rvalue_reference_t<I> &&, iter_value_t<I> const &>
);
template<typename I>
CPP_concept_bool readable = //
CPP_fragment(ranges::readable_, uncvref_t<I>);
template<typename O, typename T>
CPP_concept_fragment(writable_,
requires(O && o, T && t) //
(
*o = (T &&) t,
*(O &&) o = (T &&) t,
const_cast<iter_reference_t<O> const &&>(*o) = (T &&) t,
const_cast<iter_reference_t<O> const &&>(*(O &&) o) = (T &&) t
));
template<typename O, typename T>
CPP_concept_bool writable = //
CPP_fragment(ranges::writable_, O, T);
// clang-format on
/// \cond
namespace detail
{
#if RANGES_CXX_INLINE_VARIABLES >= RANGES_CXX_INLINE_VARIABLES_17
template<typename D>
inline constexpr bool _is_integer_like_ = std::is_integral<D>::value;
#else
template<typename D, typename = void>
constexpr bool _is_integer_like_ = std::is_integral<D>::value;
#endif
// clang-format off
template<typename D>
CPP_concept_bool integer_like_ = _is_integer_like_<D>;
// TODO additional syntactic and semantic requirements
#ifdef RANGES_WORKAROUND_MSVC_792338
template<typename D>
CPP_concept_fragment(signed_integer_like_frag_, requires()(0) &&
integer_like_<D> &&
concepts::type<decltype(std::integral_constant<bool, (D(-1) < D(0))>{})> &&
std::integral_constant<bool, (D(-1) < D(0))>::value
);
#else // ^^^ workaround / no workaround vvv
template<typename D>
CPP_concept_fragment(signed_integer_like_frag_, requires()(0) &&
integer_like_<D> &&
concepts::type<std::integral_constant<bool, (D(-1) < D(0))>> &&
std::integral_constant<bool, (D(-1) < D(0))>::value
);
#endif // RANGES_WORKAROUND_MSVC_792338
template<typename D>
CPP_concept_bool signed_integer_like_ =
CPP_fragment(detail::signed_integer_like_frag_, D);
// clang-format on
} // namespace detail
/// \endcond
// clang-format off
template<typename I>
CPP_concept_fragment(weakly_incrementable_,
requires(I i) //
(
++i,
i++,
concepts::requires_<same_as<I&, decltype(++i)>>
) &&
concepts::type<iter_difference_t<I>> &&
detail::signed_integer_like_<iter_difference_t<I>>
);
template<typename I>
CPP_concept_bool weakly_incrementable =
semiregular<I> &&
CPP_fragment(ranges::weakly_incrementable_, I);
template<typename I>
CPP_concept_fragment(incrementable_,
requires(I i) //
(
concepts::requires_<same_as<I, decltype(i++)>>
));
template<typename I>
CPP_concept_bool incrementable =
regular<I> &&
weakly_incrementable<I> &&
CPP_fragment(ranges::incrementable_, I);
template<typename I>
CPP_concept_bool input_or_output_iterator =
weakly_incrementable<I> &&
detail::dereferenceable_<I&>;
template<typename S, typename I>
CPP_concept_bool sentinel_for =
semiregular<S> &&
input_or_output_iterator<I> &&
detail::weakly_equality_comparable_with_<S, I>;
#if !CPP_CXX_CONCEPTS
template<>
CPP_concept_bool input_or_output_iterator<void> = false;
#endif
namespace defer
{
template<typename S, typename I>
CPP_concept sentinel_for =
CPP_defer(ranges::sentinel_for, S, I);
} // namespace defer
template<typename S, typename I>
CPP_concept_fragment(sized_sentinel_for_,
requires(S const & s, I const & i) //
(
s - i,
i - s,
concepts::requires_<same_as<iter_difference_t<I>, decltype(s - i)>>,
concepts::requires_<same_as<iter_difference_t<I>, decltype(i - s)>>
));
template<typename S, typename I>
CPP_concept_bool sized_sentinel_for =
// Short-circuit the test for sentinel_for if we're emulating concepts:
#if !CPP_CXX_CONCEPTS
bool(!defer::is_true<disable_sized_sentinel<std::remove_cv_t<S>,
std::remove_cv_t<I>>> &&
defer::sentinel_for<S, I>) &&
#else
(!disable_sized_sentinel<std::remove_cv_t<S>, std::remove_cv_t<I>>) &&
defer::sentinel_for<S, I> &&
#endif
CPP_fragment(ranges::sized_sentinel_for_, S, I);
template<typename Out, typename T>
CPP_concept_fragment(output_iterator_,
requires(Out o, T && t) //
(
*o++ = (T &&) t
));
template<typename Out, typename T>
CPP_concept_bool output_iterator =
input_or_output_iterator<Out> &&
writable<Out, T> &&
CPP_fragment(ranges::output_iterator_, Out, T);
template<typename I, typename Tag>
CPP_concept_fragment(with_category_, requires()(0) &&
derived_from<detail::iter_concept_t<I>, Tag>
);
template<typename I>
CPP_concept_bool input_iterator =
input_or_output_iterator<I> &&
readable<I> &&
CPP_fragment(ranges::with_category_, I, std::input_iterator_tag);
template<typename I>
CPP_concept_bool forward_iterator =
input_iterator<I> &&
incrementable<I> &&
sentinel_for<I, I> &&
CPP_fragment(ranges::with_category_, I, std::forward_iterator_tag);
template<typename I>
CPP_concept_fragment(bidirectional_iterator_,
requires(I i) //
(
--i,
i--,
concepts::requires_<same_as<I&, decltype(--i)>>,
concepts::requires_<same_as<I, decltype(i--)>>
));
template<typename I>
CPP_concept_bool bidirectional_iterator =
forward_iterator<I> &&
CPP_fragment(ranges::bidirectional_iterator_, I) &&
CPP_fragment(ranges::with_category_, I, std::bidirectional_iterator_tag);
template<typename I>
CPP_concept_fragment(random_access_iterator_,
requires(I i, iter_difference_t<I> n)
(
i + n,
n + i,
i - n,
i += n,
i -= n,
concepts::requires_<same_as<decltype(i + n), I>>,
concepts::requires_<same_as<decltype(n + i), I>>,
concepts::requires_<same_as<decltype(i - n), I>>,
concepts::requires_<same_as<decltype(i += n), I&>>,
concepts::requires_<same_as<decltype(i -= n), I&>>,
concepts::requires_<same_as<decltype(i[n]), iter_reference_t<I>>>
));
template<typename I>
CPP_concept_bool random_access_iterator =
bidirectional_iterator<I> &&
totally_ordered<I> &&
sized_sentinel_for<I, I> &&
CPP_fragment(ranges::random_access_iterator_, I) &&
CPP_fragment(ranges::with_category_, I, std::random_access_iterator_tag);
template<typename I>
CPP_concept_fragment(contiguous_iterator_, requires()(0) &&
std::is_lvalue_reference<iter_reference_t<I>>::value &&
same_as<iter_value_t<I>, uncvref_t<iter_reference_t<I>>> &&
derived_from<detail::iter_concept_t<I>, ranges::contiguous_iterator_tag>
);
template<typename I>
CPP_concept_bool contiguous_iterator =
random_access_iterator<I> &&
CPP_fragment(ranges::contiguous_iterator_, I);
// clang-format on
/////////////////////////////////////////////////////////////////////////////////////
// iterator_tag_of
template<typename Rng>
using iterator_tag_of = //
std::enable_if_t< //
input_iterator<Rng>, //
detail::if_then_t< //
contiguous_iterator<Rng>, //
ranges::contiguous_iterator_tag, //
detail::if_then_t< //
random_access_iterator<Rng>, //
std::random_access_iterator_tag, //
detail::if_then_t< //
bidirectional_iterator<Rng>, //
std::bidirectional_iterator_tag, //
detail::if_then_t< //
forward_iterator<Rng>, //
std::forward_iterator_tag, //
std::input_iterator_tag>>>>>;
/// \cond
namespace detail
{
template<typename, bool>
struct iterator_category_
{};
template<typename I>
struct iterator_category_<I, true>
{
using type = iterator_tag_of<I>;
};
template<typename T, typename U = meta::_t<std::remove_const<T>>>
using iterator_category = iterator_category_<U, (bool)input_iterator<U>>;
} // namespace detail
/// \endcond
/// \cond
// Generally useful to know if an iterator is single-pass or not:
// clang-format off
template<typename I>
CPP_concept_bool single_pass_iterator_ =
input_or_output_iterator<I> && !forward_iterator<I>;
// clang-format on
/// \endcond
////////////////////////////////////////////////////////////////////////////////////////////
// indirect_result_t
template<typename Fun, typename... Is>
using indirect_result_t =
detail::enable_if_t<(bool)and_v<(bool)readable<Is>...>,
invoke_result_t<Fun, iter_reference_t<Is>...>>;
/// \cond
namespace detail
{
// clang-format off
template<typename T1, typename T2, typename T3, typename T4>
CPP_concept_fragment(common_reference_with_4_, requires()(0) &&
concepts::type<common_reference_t<T1, T2, T3, T4>> &&
convertible_to<T1, common_reference_t<T1, T2, T3, T4>> &&
convertible_to<T2, common_reference_t<T1, T2, T3, T4>> &&
convertible_to<T3, common_reference_t<T1, T2, T3, T4>> &&
convertible_to<T4, common_reference_t<T1, T2, T3, T4>>
);
// axiom: all permutations of T1,T2,T3,T4 have the same
// common reference type.
template<typename F, typename I>
CPP_concept_fragment(indirectly_unary_invocable_frag_, requires()(0) &&
invocable<F &, iter_value_t<I> &> &&
invocable<F &, iter_reference_t<I>> &&
invocable<F &, iter_common_reference_t<I>> &&
common_reference_with<
invoke_result_t<F &, iter_value_t<I> &>,
invoke_result_t<F &, iter_reference_t<I>>>
);
template<typename F, typename I>
CPP_concept_bool indirectly_unary_invocable_ =
readable<I> &&
CPP_fragment(detail::indirectly_unary_invocable_frag_, F, I);
// clang-format on
} // namespace detail
/// \endcond
// clang-format off
template<typename F, typename I>
CPP_concept_bool indirectly_unary_invocable =
detail::indirectly_unary_invocable_<F, I> &&
copy_constructible<F>;
template<typename F, typename I>
CPP_concept_fragment(indirectly_regular_unary_invocable_, requires()(0) &&
regular_invocable<F &, iter_value_t<I> &> &&
regular_invocable<F &, iter_reference_t<I>> &&
regular_invocable<F &, iter_common_reference_t<I>> &&
common_reference_with<
invoke_result_t<F &, iter_value_t<I> &>,
invoke_result_t<F &, iter_reference_t<I>>>
);
template<typename F, typename I>
CPP_concept_bool indirectly_regular_unary_invocable =
readable<I> &&
copy_constructible<F> &&
CPP_fragment(ranges::indirectly_regular_unary_invocable_, F, I);
/// \cond
// Non-standard indirect invocable concepts
template<typename F, typename I1, typename I2>
CPP_concept_fragment(indirectly_binary_invocable_frag_, requires()(0) &&
invocable<F &, iter_value_t<I1> &, iter_value_t<I2> &> &&
invocable<F &, iter_value_t<I1> &, iter_reference_t<I2>> &&
invocable<F &, iter_reference_t<I1>, iter_value_t<I2> &> &&
invocable<F &, iter_reference_t<I1>, iter_reference_t<I2>> &&
invocable<F &, iter_common_reference_t<I1>, iter_common_reference_t<I2>> &&
CPP_fragment(detail::common_reference_with_4_,
invoke_result_t<F &, iter_value_t<I1> &, iter_value_t<I2> &>,
invoke_result_t<F &, iter_value_t<I1> &, iter_reference_t<I2>>,
invoke_result_t<F &, iter_reference_t<I1>, iter_value_t<I2> &>,
invoke_result_t<F &, iter_reference_t<I1>, iter_reference_t<I2>>)
);
template<typename F, typename I1, typename I2>
CPP_concept_bool indirectly_binary_invocable_ =
readable<I1> && readable<I2> &&
copy_constructible<F> &&
CPP_fragment(ranges::indirectly_binary_invocable_frag_, F, I1, I2);
template<typename F, typename I1, typename I2>
CPP_concept_fragment(indirectly_regular_binary_invocable_frag_, requires()(0) &&
regular_invocable<F &, iter_value_t<I1> &, iter_value_t<I2> &> &&
regular_invocable<F &, iter_value_t<I1> &, iter_reference_t<I2>> &&
regular_invocable<F &, iter_reference_t<I1>, iter_value_t<I2> &> &&
regular_invocable<F &, iter_reference_t<I1>, iter_reference_t<I2>> &&
regular_invocable<F &, iter_common_reference_t<I1>, iter_common_reference_t<I2>> &&
CPP_fragment(detail::common_reference_with_4_,
invoke_result_t<F &, iter_value_t<I1> &, iter_value_t<I2> &>,
invoke_result_t<F &, iter_value_t<I1> &, iter_reference_t<I2>>,
invoke_result_t<F &, iter_reference_t<I1>, iter_value_t<I2> &>,
invoke_result_t<F &, iter_reference_t<I1>, iter_reference_t<I2>>)
);
template<typename F, typename I1, typename I2>
CPP_concept_bool indirectly_regular_binary_invocable_ =
readable<I1> && readable<I2> &&
copy_constructible<F> &&
CPP_fragment(ranges::indirectly_regular_binary_invocable_frag_, F, I1, I2);
/// \endcond
template<typename F, typename I>
CPP_concept_fragment(indirect_unary_predicate_, requires()(0) &&
predicate<F &, iter_value_t<I> &> &&
predicate<F &, iter_reference_t<I>> &&
predicate<F &, iter_common_reference_t<I>>
);
template<typename F, typename I>
CPP_concept_bool indirect_unary_predicate =
readable<I> &&
copy_constructible<F> &&
CPP_fragment(ranges::indirect_unary_predicate_, F, I);
template<typename F, typename I1, typename I2>
CPP_concept_fragment(indirect_binary_predicate_frag_, requires()(0) &&
predicate<F &, iter_value_t<I1> &, iter_value_t<I2> &> &&
predicate<F &, iter_value_t<I1> &, iter_reference_t<I2>> &&
predicate<F &, iter_reference_t<I1>, iter_value_t<I2> &> &&
predicate<F &, iter_reference_t<I1>, iter_reference_t<I2>> &&
predicate<F &, iter_common_reference_t<I1>, iter_common_reference_t<I2>>
);
template<typename F, typename I1, typename I2>
CPP_concept_bool indirect_binary_predicate_ =
readable<I1> && readable<I2> &&
copy_constructible<F> &&
CPP_fragment(ranges::indirect_binary_predicate_frag_, F, I1, I2);
template<typename F, typename I1, typename I2>
CPP_concept_fragment(indirect_relation_, requires()(0) &&
relation<F &, iter_value_t<I1> &, iter_value_t<I2> &> &&
relation<F &, iter_value_t<I1> &, iter_reference_t<I2>> &&
relation<F &, iter_reference_t<I1>, iter_value_t<I2> &> &&
relation<F &, iter_reference_t<I1>, iter_reference_t<I2>> &&
relation<F &, iter_common_reference_t<I1>, iter_common_reference_t<I2>>
);
template<typename F, typename I1, typename I2 = I1>
CPP_concept_bool indirect_relation =
readable<I1> && readable<I2> &&
copy_constructible<F> &&
CPP_fragment(ranges::indirect_relation_, F, I1, I2);
template<typename F, typename I1, typename I2>
CPP_concept_fragment(indirect_strict_weak_order_, requires()(0) &&
strict_weak_order<F &, iter_value_t<I1> &, iter_value_t<I2> &> &&
strict_weak_order<F &, iter_value_t<I1> &, iter_reference_t<I2>> &&
strict_weak_order<F &, iter_reference_t<I1>, iter_value_t<I2> &> &&
strict_weak_order<F &, iter_reference_t<I1>, iter_reference_t<I2>> &&
strict_weak_order<F &, iter_common_reference_t<I1>, iter_common_reference_t<I2>>
);
template<typename F, typename I1, typename I2 = I1>
CPP_concept_bool indirect_strict_weak_order =
readable<I1> && readable<I2> &&
copy_constructible<F> &&
CPP_fragment(ranges::indirect_strict_weak_order_, F, I1, I2);
// clang-format on
////////////////////////////////////////////////////////////////////////////////////////////
// projected struct, for "projecting" a readable with a unary callable
/// \cond
namespace detail
{
RANGES_DIAGNOSTIC_PUSH
RANGES_DIAGNOSTIC_IGNORE_UNDEFINED_INTERNAL
template<typename I, typename Proj>
struct projected_
{
using reference = indirect_result_t<Proj &, I>;
using value_type = uncvref_t<reference>;
reference operator*() const;
};
RANGES_DIAGNOSTIC_POP
template<typename Proj>
struct select_projected_
{
template<typename I>
using apply =
detail::enable_if_t<(bool)indirectly_regular_unary_invocable<Proj, I>,
detail::projected_<I, Proj>>;
};
template<>
struct select_projected_<identity>
{
template<typename I>
using apply = detail::enable_if_t<(bool)readable<I>, I>;
};
} // namespace detail
/// \endcond
template<typename I, typename Proj>
using projected = typename detail::select_projected_<Proj>::template apply<I>;
template<typename I, typename Proj>
struct incrementable_traits<detail::projected_<I, Proj>> : incrementable_traits<I>
{};
// clang-format off
template<typename I, typename O>
CPP_concept_fragment(indirectly_movable_, requires()(0) &&
writable<O, iter_rvalue_reference_t<I>>
);
template<typename I, typename O>
CPP_concept_bool indirectly_movable =
readable<I> && CPP_fragment(ranges::indirectly_movable_, I, O);
template<typename I, typename O>
CPP_concept_fragment(indirectly_movable_storable_, requires()(0) &&
writable<O, iter_value_t<I>> &&
movable<iter_value_t<I>> &&
constructible_from<iter_value_t<I>, iter_rvalue_reference_t<I>> &&
assignable_from<iter_value_t<I> &, iter_rvalue_reference_t<I>>
);
template<typename I, typename O>
CPP_concept_bool indirectly_movable_storable =
indirectly_movable<I, O> &&
CPP_fragment(ranges::indirectly_movable_storable_, I, O);
template<typename I, typename O>
CPP_concept_fragment(indirectly_copyable_, requires()(0) &&
writable<O, iter_reference_t<I>>
);
template<typename I, typename O>
CPP_concept_bool indirectly_copyable =
readable<I> && CPP_fragment(ranges::indirectly_copyable_, I, O);
template<typename I, typename O>
CPP_concept_fragment(indirectly_copyable_storable_, requires()(0) &&
writable<O, iter_value_t<I> const &> &&
copyable<iter_value_t<I>> &&
constructible_from<iter_value_t<I>, iter_reference_t<I>> &&
assignable_from<iter_value_t<I> &, iter_reference_t<I>>
);
template<typename I, typename O>
CPP_concept_bool indirectly_copyable_storable =
indirectly_copyable<I, O> &&
CPP_fragment(ranges::indirectly_copyable_storable_, I, O);
template<typename I1, typename I2>
CPP_concept_fragment(indirectly_swappable_,
requires(I1 const i1, I2 const i2) //
(
ranges::iter_swap(i1, i2),
ranges::iter_swap(i1, i1),
ranges::iter_swap(i2, i2),
ranges::iter_swap(i2, i1)
));
template<typename I1, typename I2 = I1>
CPP_concept_bool indirectly_swappable =
readable<I1> && readable<I2> &&
CPP_fragment(ranges::indirectly_swappable_, I1, I2);
template<typename C, typename I1, typename P1, typename I2, typename P2>
CPP_concept_fragment(projected_indirect_relation_, requires()(0) &&
indirect_relation<C, projected<I1, P1>, projected<I2, P2>>
);
template<typename I1, typename I2, typename C, typename P1 = identity,
typename P2 = identity>
CPP_concept_bool indirectly_comparable =
CPP_fragment(ranges::projected_indirect_relation_, C, I1, P1, I2, P2);
////////////////////////////////////////////////////////////////////////////////////////////
// Composite concepts for use defining algorithms:
template<typename I>
CPP_concept_bool permutable =
forward_iterator<I> &&
indirectly_swappable<I, I> &&
indirectly_movable_storable<I, I>;
template<typename C, typename I1, typename P1, typename I2, typename P2>
CPP_concept_fragment(projected_indirect_strict_weak_order_, requires()(0) &&
indirect_strict_weak_order<C, projected<I1, P1>, projected<I2, P2>>
);
template<typename I1, typename I2, typename Out, typename C = less,
typename P1 = identity, typename P2 = identity>
CPP_concept_bool mergeable =
input_iterator<I1> &&
input_iterator<I2> &&
weakly_incrementable<Out> &&
indirectly_copyable<I1, Out> &&
indirectly_copyable<I2, Out> &&
CPP_fragment(ranges::projected_indirect_strict_weak_order_, C, I1, P1, I2, P2);
template<typename I, typename C = less, typename P = identity>
CPP_concept_bool sortable =
permutable<I> &&
CPP_fragment(ranges::projected_indirect_strict_weak_order_, C, I, P, I, P);
// clang-format on
struct sentinel_tag
{};
struct sized_sentinel_tag : sentinel_tag
{};
template<typename S, typename I>
using sentinel_tag_of = //
std::enable_if_t< //
sentinel_for<S, I>, //
detail::if_then_t< //
sized_sentinel_for<S, I>, //
sized_sentinel_tag, //
sentinel_tag>>;
// Deprecated things:
/// \cond
template<typename I>
using iterator_category RANGES_DEPRECATED(
"iterator_category is deprecated. Use the iterator concepts instead") =
detail::iterator_category<I>;
template<typename I>
using iterator_category_t RANGES_DEPRECATED(
"iterator_category_t is deprecated. Use the iterator concepts instead") =
meta::_t<detail::iterator_category<I>>;
template<typename Fun, typename... Is>
using indirect_invoke_result_t RANGES_DEPRECATED(
"Please switch to indirect_result_t") = indirect_result_t<Fun, Is...>;
template<typename Fun, typename... Is>
struct RANGES_DEPRECATED("Please switch to indirect_result_t") indirect_invoke_result
: meta::defer<indirect_result_t, Fun, Is...>
{};
template<typename Sig>
struct indirect_result_of
{};
template<typename Fun, typename... Is>
struct RANGES_DEPRECATED("Please switch to indirect_result_t")
indirect_result_of<Fun(Is...)> : meta::defer<indirect_result_t, Fun, Is...>
{};
template<typename Sig>
using indirect_result_of_t RANGES_DEPRECATED("Please switch to indirect_result_t") =
meta::_t<indirect_result_of<Sig>>;
/// \endcond
namespace cpp20
{
using ranges::bidirectional_iterator;
using ranges::contiguous_iterator;
using ranges::forward_iterator;
using ranges::incrementable;
using ranges::indirect_relation;
using ranges::indirect_result_t;
using ranges::indirect_strict_weak_order;
using ranges::indirect_unary_predicate;
using ranges::indirectly_comparable;
using ranges::indirectly_copyable;
using ranges::indirectly_copyable_storable;
using ranges::indirectly_movable;
using ranges::indirectly_movable_storable;
using ranges::indirectly_regular_unary_invocable;
using ranges::indirectly_swappable;
using ranges::indirectly_unary_invocable;
using ranges::input_iterator;
using ranges::input_or_output_iterator;
using ranges::mergeable;
using ranges::output_iterator;
using ranges::permutable;
using ranges::projected;
using ranges::random_access_iterator;
using ranges::readable;
using ranges::sentinel_for;
using ranges::sized_sentinel_for;
using ranges::sortable;
using ranges::weakly_incrementable;
using ranges::writable;
} // namespace cpp20
/// @}
} // namespace ranges
#ifdef _GLIBCXX_DEBUG
// HACKHACK: workaround underconstrained operator- for libstdc++ debug iterator wrapper
// by intentionally creating an ambiguity when the wrapped types don't support the
// necessary operation.
namespace __gnu_debug
{
template<typename I1, typename I2, typename Seq>
auto operator-(_Safe_iterator<I1, Seq> const &, _Safe_iterator<I2, Seq> const &)
-> CPP_ret(void)( //
requires(!::ranges::sized_sentinel_for<I1, I2>)) = delete;
template<typename I1, typename Seq>
auto operator-(_Safe_iterator<I1, Seq> const &, _Safe_iterator<I1, Seq> const &)
-> CPP_ret(void)( //
requires(!::ranges::sized_sentinel_for<I1, I1>)) = delete;
} // namespace __gnu_debug
#endif
#if defined(__GLIBCXX__) || (defined(_LIBCPP_VERSION) && _LIBCPP_VERSION <= 3900)
// HACKHACK: workaround libc++ (https://llvm.org/bugs/show_bug.cgi?id=28421)
// and libstdc++ (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71771)
// underconstrained operator- for reverse_iterator by disabling sized_sentinel_for
// when the base iterators do not model sized_sentinel_for.
namespace ranges
{
template<typename S, typename I>
/*inline*/ constexpr bool
disable_sized_sentinel<std::reverse_iterator<S>, std::reverse_iterator<I>> =
!static_cast<bool>(sized_sentinel_for<I, S>);
} // namespace ranges
#endif // defined(__GLIBCXX__) || (defined(_LIBCPP_VERSION) && _LIBCPP_VERSION <= 3900)
#include <range/v3/detail/reenable_warnings.hpp>
#endif // RANGES_V3_ITERATOR_CONCEPTS_HPP