NAME¶

std::ranges::lazy_split_view::outer_iterator - std::ranges::lazy_split_view::outer_iterator

Synopsis¶

template< bool Const > (since C++20)
struct /* outer_iterator */; (exposition only*)

The return type of lazy_split_view::begin, and of lazy_split_view::end when the
underlying view is a common_range and forward_range.

If either V or Pattern is not a simple view (e.g. if ranges::iterator_t<const V> is
invalid or different from ranges::iterator_t<V>), Const is true for iterators
returned from the const overloads, and false otherwise. If V is a simple view, Const
is true if and only if V is a forward_range.

Member types¶

Member type Definition
const ranges::lazy_split_view if Const is true, otherwise
Parent ranges::lazy_split_view
(exposition-only member type*)
Base const V if Const is true, otherwise V
(exposition-only member type*)
iterator_concept (C++20) std::forward_iterator_tag if Base models forward_range,
otherwise std::input_iterator_tag
iterator_category (C++20) std::input_iterator_tag if Base models forward_range. Not
present otherwise.
value_type (C++20) ranges::lazy_iterator_view<V, Pattern>
::/* outer_iterator */<Const>::value_type
difference_type (C++20) ranges::range_difference_t<Base>.

Data members

Member name Definition
A pointer of type Parent* to the parent lazy_split_view
parent_ (private) object
(exposition-only member object*)
An iterator of type ranges::iterator_t<Base> into the
current_ (private) underlying view; present only if V models forward_range
(exposition-only member object*)
A boolean flag that indicates whether an empty trailing
trailing_empty_ (private) subrange (if any) was reached
(exposition-only member object*)

Member functions¶

constructor constructs an iterator
(C++20) (public member function)
operator* returns the current subrange
(C++20) (public member function)
operator++ advances the iterator
operator++(int) (public member function)
(C++20)
cur returns conditionally a reference to the current_ (if present) or to
(C++20) the *parent_->current_
(exposition-only member function*)

Member functions¶

std::ranges::lazy_split_view::outer_iterator ::outer_iterator

/* outer_iterator */() = default; (1) (since C++20)
constexpr explicit /* outer_iterator */( Parent& parent ) (2) (since C++20)
requires (!ranges::forward_range<Base>);
constexpr /* outer_iterator */( Parent& parent,

ranges::iterator_t<Base> current ) (3) (since C++20)

requires ranges::forward_range<Base>;
constexpr /* outer_iterator */( /* outer_iterator */<!Const> i )

requires Const && std::convertible_to<ranges::iterator_t<V>, (4) (since C++20)

ranges::iterator_t<Base>>;

1) Value initializes the non-static data members with their default member
initializer, that is:
* parent_ = nullptr;,
* current_ = iterator_t<Base>(); (present only if V models forward_range),
2) Initializes parent_ with std::addressof(parent).
3) Initializes parent_ with std::addressof(parent) and current_ with
std::move(current).
4) Initializes parent_ with i.parent_, current_ with std::move(i.current_), and
trailing_empty_ with t.trailing_empty_.

The trailing_empty_ is initialized with its default member initializer to false.

std::ranges::lazy_split_view::outer_iterator ::operator*

constexpr value_type operator*() const; (since C++20)

Equivalent to return value_type{*this};.

std::ranges::lazy_split_view::outer_iterator ::operator++

constexpr /* outer_iterator */& operator++(); (1) (since C++20)
constexpr decltype(auto) operator++(int); (2) (since C++20)

1) The function body is equivalent to

const auto end = ranges::end(parent_->base_);
if (/* cur */() == end)
{
trailing_empty_ = false;
return *this;
}
const auto [pbegin, pend] = ranges::subrange{parent_->pattern_};
if (pbegin == pend)
++/* cur */();
else if constexpr (/* tiny_range */<Pattern>)
{
/* cur */() = ranges::find(std::move(/* cur */()), end, *pbegin);
if (/* cur */() != end)
{
++/* cur */();
if (/* cur */() == end)
trailing_empty_ = true;
}
}
else
{
do
{
auto [b, p] = ranges::mismatch(/* cur */(), end, pbegin, pend);
if (p == pend)
{
/* cur */() = b;
if (/* cur */() == end)
trailing_empty_ = true;
break; // The pattern matched; skip it
}
} while (++/* cur */() != end);
}
return *this;

2) Equivalent to

if constexpr (ranges::forward_range<Base>)
{
auto tmp = *this;
++*this;
return tmp;
}
else
{
++*this; // no return statement
}

std::ranges::lazy_split_view::outer_iterator ::cur ()

constexpr auto& /* cur */() noexcept; (1) (since C++20)
(exposition only*)
constexpr auto& /* cur */() const noexcept; (2) (since C++20)
(exposition only*)

This convenience member function is referred to from /* outer_iterator
*/::operator++(), from the non-member operator==(const /* outer_iterator */&,
std::default_sentinel_t), and from some member functions of the possible
implementation of inner_iterator.

1,2) Equivalent to

if constexpr (ranges::forward_range<V>)
return current_;
else
return *parent->current_;

Non-member functions¶

operator== compares the underlying iterators or the underlying iterator and
(C++20) std::default_sentinel
(function)

operator==(std::ranges::split_view::outer_iterator)

friend constexpr bool operator==( const /* outer_iterator */& x,

const /* outer_iterator */& y ) (1) (since C++20)

requires forward_range<Base>;
friend constexpr bool operator==( const /* outer_iterator */& x, (2) (since C++20)
std::default_sentinel_t );

1) Equivalent to return x.current_ == y.current_ and x.trailing_empty_ ==
y.trailing_empty_;.
2) Equivalent to return x./* cur */() == ranges::end(x.parent_->base_) and
!x.trailing_empty_;.

The != operator is synthesized from operator==.

These functions are not visible to ordinary unqualified or qualified lookup, and can
only be found by argument-dependent lookup when
std::ranges::split_view::outer_iterator is an associated class of the arguments.

Nested classes

value_type the value type of the outer_iterator
(C++20) (public member class)

Defect reports

The following behavior-changing defect reports were applied retroactively to
previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 3904 C++20 trailing_empty_ was not initialized in initialized
constructor overload (4)