[range.elements.iterator] (original) (raw)
25 Ranges library [ranges]
25.7 Range adaptors [range.adaptors]
25.7.23 Elements view [range.elements]
25.7.23.3 Class template elements_view::iterator [range.elements.iterator]
namespace std::ranges { template<input_range V, size_t N> requires view<V> && has-tuple-element<range_value_t<V>, N> && has-tuple-element<remove_reference_t<range_reference_t<V>>, N> && returnable-element<range_reference_t<V>, N> template<bool Const> class elements_view<V, N>::iterator { using Base = maybe-const<Const, V>; iterator_t<_Base_> current_ = iterator_t<_Base_>(); static constexpr decltype(auto) get-element(const iterator_t<_Base_>& i); public: using iterator_concept = see below;using iterator_category = see below; using value_type = remove_cvref_t<tuple_element_t<N, range_value_t<_Base_>>>;using difference_type = range_difference_t<_Base_>;iterator() requires default_initializable<iterator_t<_Base_>> = default;constexpr explicit iterator(iterator_t<_Base_> current);constexpr iterator(iterator<!Const> i) requires Const && convertible_to<iterator_t<V>, iterator_t<_Base_>>;constexpr const iterator_t<_Base_>& base() const & noexcept;constexpr iterator_t<_Base_> base() &&;constexpr decltype(auto) operator*() const { return get-element(current_); } constexpr iterator& operator++();constexpr void operator++(int);constexpr iterator operator++(int) requires forward_range<_Base_>;constexpr iterator& operator--() requires bidirectional_range<_Base_>;constexpr iterator operator--(int) requires bidirectional_range<_Base_>;constexpr iterator& operator+=(difference_type x) requires random_access_range<_Base_>;constexpr iterator& operator-=(difference_type x) requires random_access_range<_Base_>;constexpr decltype(auto) operator[](difference_type n) const requires random_access_range<_Base_> { return get-element(current_ + n); } friend constexpr bool operator==(const iterator& x, const iterator& y) requires equality_comparable<iterator_t<_Base_>>;friend constexpr bool operator<(const _iterator_& x, const _iterator_& y) requires random_access_range<_Base_>;friend constexpr bool operator>(const iterator& x, const iterator& y) requires random_access_range<_Base_>;friend constexpr bool operator<=(const _iterator_& x, const _iterator_& y) requires random_access_range<_Base_>;friend constexpr bool operator>=(const iterator& x, const iterator& y) requires random_access_range<_Base_>;friend constexpr auto operator<=>(const iterator& x, const iterator& y) requires random_access_range<_Base_> && three_way_comparable<iterator_t<_Base_>>;friend constexpr iterator operator+(const iterator& x, difference_type y) requires random_access_range<_Base_>;friend constexpr iterator operator+(difference_type x, const iterator& y) requires random_access_range<_Base_>;friend constexpr iterator operator-(const iterator& x, difference_type y) requires random_access_range<_Base_>;friend constexpr difference_type operator-(const iterator& x, const iterator& y) requires sized_sentinel_for<iterator_t<_Base_>, iterator_t<_Base_>>;};}
The member typedef-name iterator_conceptis defined as follows:
- Otherwise, if Base models bidirectional_range, then iterator_concept denotes bidirectional_iterator_tag.
- Otherwise, if Base models forward_range, then iterator_concept denotes forward_iterator_tag.
- Otherwise, iterator_concept denotes input_iterator_tag.
In that case, iterator_category is defined as follows: Let C denote the typeiterator_traits<iterator_t<_Base_>>::iterator_category.
- If std::get<N>(*current_) is an rvalue,iterator_category denotes input_iterator_tag.
- Otherwise, if C models derived_from<random_access_iterator_tag>,iterator_category denotes random_access_iterator_tag.
- Otherwise, iterator_category denotes C.
static constexpr decltype(auto) _get-element_(const iterator_t<_Base_>& i);
Effects: Equivalent to:if constexpr (is_reference_v<range_reference_t<_Base_>>) { return std::get<N>(*i);} else { using E = remove_cv_t<tuple_element_t<N, range_reference_t<_Base_>>>;return static_cast<E>(std::get<N>(*i));}
constexpr explicit _iterator_(iterator_t<_Base_> current);
Effects: Initializes current_ with std::move(current).
constexpr _iterator_(_iterator_<!Const> i) requires Const && [convertible_to](concept.convertible#concept:convertible%5Fto "18.4.4 Concept convertible_to [concept.convertible]")<iterator_t<V>, iterator_t<_Base_>>;
Effects: Initializes current_ with std::move(i.current_).
constexpr const iterator_t<_Base_>& base() const & noexcept;
Effects: Equivalent to: return current_;
constexpr iterator_t<_Base_> base() &&;
Effects: Equivalent to: return std::move(current_);
constexpr _iterator_& operator++();
Effects: Equivalent to:++current_;return *this;
constexpr void operator++(int);
Effects: Equivalent to: ++current_.
Effects: Equivalent to:auto temp = *this;++current_;return temp;
Effects: Equivalent to:--current_;return *this;
Effects: Equivalent to:auto temp = *this;--current_;return temp;
Effects: Equivalent to:current_ += n;return *this;
Effects: Equivalent to:current_ -= n;return *this;
friend constexpr bool operator==(const _iterator_& x, const _iterator_& y) requires [equality_comparable](concept.equalitycomparable#concept:equality%5Fcomparable "18.5.4 Concept equality_comparable [concept.equalitycomparable]")<_Base_>;
Effects: Equivalent to: return x.current_ == y.current_;
friend constexpr bool operator<(const _iterator_& x, const _iterator_& y) requires [random_access_range](range.refinements#concept:random%5Faccess%5Frange "25.4.6 Other range refinements [range.refinements]")<_Base_>;
Effects: Equivalent to: return x.current_ < y.current_;
friend constexpr bool operator>(const _iterator_& x, const _iterator_& y) requires [random_access_range](range.refinements#concept:random%5Faccess%5Frange "25.4.6 Other range refinements [range.refinements]")<_Base_>;
Effects: Equivalent to: return y < x;
friend constexpr bool operator<=(const _iterator_& x, const _iterator_& y) requires [random_access_range](range.refinements#concept:random%5Faccess%5Frange "25.4.6 Other range refinements [range.refinements]")<_Base_>;
Effects: Equivalent to: return !(y < x);
friend constexpr bool operator>=(const _iterator_& x, const _iterator_& y) requires [random_access_range](range.refinements#concept:random%5Faccess%5Frange "25.4.6 Other range refinements [range.refinements]")<_Base_>;
Effects: Equivalent to: return !(x < y);
Effects: Equivalent to: return x.current_ <=> y.current_;
friend constexpr _iterator_ operator+(const _iterator_& x, difference_type y) requires [random_access_range](range.refinements#concept:random%5Faccess%5Frange "25.4.6 Other range refinements [range.refinements]")<_Base_>;
Effects: Equivalent to: return iterator{x} += y;
friend constexpr _iterator_ operator+(difference_type x, const _iterator_& y) requires [random_access_range](range.refinements#concept:random%5Faccess%5Frange "25.4.6 Other range refinements [range.refinements]")<_Base_>;
Effects: Equivalent to: return y + x;
friend constexpr _iterator_ operator-(const _iterator_& x, difference_type y) requires [random_access_range](range.refinements#concept:random%5Faccess%5Frange "25.4.6 Other range refinements [range.refinements]")<_Base_>;
Effects: Equivalent to: return iterator{x} -= y;
friend constexpr difference_type operator-(const _iterator_& x, const _iterator_& y) requires [sized_sentinel_for](iterator.concept.sizedsentinel#concept:sized%5Fsentinel%5Ffor "24.3.4.8 Concept sized_sentinel_for [iterator.concept.sizedsentinel]")<iterator_t<_Base_>, iterator_t<_Base_>>;
Effects: Equivalent to: return x.current_ - y.current_;