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// { dg-do compile { target c++26 } }
#include <concepts>
#include <format>
#include <iterator>
#include <optional>
#include <ranges>
#include <string_view>
#include <vector>
#include <testsuite_hooks.h>
template<typename O>
constexpr
void
test_range_concepts()
{
static_assert(std::ranges::contiguous_range<O>);
static_assert(std::ranges::sized_range<O>);
static_assert(std::ranges::common_range<O>);
static_assert(!std::ranges::borrowed_range<O>);
// an optional<const T> is not assignable, and therefore does not satisfy ranges::view
using T = typename O::value_type;
constexpr bool is_const_opt = std::is_const_v<T>;
static_assert(std::ranges::view<O> == !is_const_opt);
static_assert(std::ranges::viewable_range<O> == !is_const_opt);
}
template<typename O>
constexpr
void
test_iterator_concepts()
{
using T = typename O::value_type;
using iterator = typename O::iterator;
static_assert(std::contiguous_iterator<iterator>);
static_assert(std::is_same_v<typename std::iterator_traits<iterator>::value_type, std::remove_cv_t<T>>);
static_assert(std::is_same_v<std::iter_value_t<iterator>, std::remove_cv_t<T>>);
static_assert(std::is_same_v<typename std::iterator_traits<iterator>::reference, T&>);
static_assert(std::is_same_v<std::iter_reference_t<iterator>, T&>);
using const_iterator = typename O::const_iterator;
static_assert(std::contiguous_iterator<const_iterator>);
static_assert(std::is_same_v<typename std::iterator_traits<const_iterator>::value_type, std::remove_cv_t<T>>);
static_assert(std::is_same_v<std::iter_value_t<const_iterator>, std::remove_cv_t<T>>);
static_assert(std::is_same_v<typename std::iterator_traits<const_iterator>::reference, const T&>);
static_assert(std::is_same_v<std::iter_reference_t<const_iterator>, const T&>);
}
template<typename O>
constexpr
void
test_empty()
{
O empty;
VERIFY(!empty);
VERIFY(empty.begin() == empty.end());
VERIFY(std::as_const(empty).begin() == std::as_const(empty).end());
VERIFY(std::ranges::empty(empty));
VERIFY(std::ranges::empty(std::as_const(empty)));
VERIFY(std::ranges::empty(empty | std::views::as_const));
VERIFY(std::ranges::size(empty) == 0);
VERIFY(std::ranges::size(std::as_const(empty)) == 0);
size_t count = 0;
for (const auto& x : empty)
++count;
VERIFY(count == 0);
}
template<typename O, typename T>
constexpr
void
test_non_empty(const T& value)
{
O non_empty = std::make_optional(value);
VERIFY(non_empty);
VERIFY(*non_empty == value);
VERIFY(non_empty.begin() != non_empty.end());
VERIFY(non_empty.begin() < non_empty.end());
VERIFY(std::as_const(non_empty).begin() != std::as_const(non_empty).end());
VERIFY(std::as_const(non_empty).begin() < std::as_const(non_empty).end());
VERIFY(!std::ranges::empty(non_empty));
VERIFY(!std::ranges::empty(std::as_const(non_empty)));
VERIFY(!std::ranges::empty(non_empty | std::views::as_const));
VERIFY(std::ranges::size(non_empty) == 1);
VERIFY(std::ranges::size(std::as_const(non_empty)) == 1);
size_t count = 0;
for (const auto& x : non_empty)
++count;
VERIFY(count == 1);
if constexpr (!std::is_const_v<typename O::value_type>) {
for (auto& x : non_empty)
x = T{};
VERIFY(non_empty);
VERIFY(*non_empty == T{});
}
}
template<typename T>
constexpr
void
test(const T& value)
{
using O = std::optional<T>;
test_range_concepts<O>();
test_iterator_concepts<O>();
test_empty<O>();
test_non_empty<O>(value);
static_assert(!std::formattable<O, char>);
static_assert(!std::formattable<O, wchar_t>);
static_assert(std::format_kind<O> == std::range_format::disabled);
}
constexpr
void
range_chain_example() // from P3168
{
std::vector<int> v{2, 3, 4, 5, 6, 7, 8, 9, 1};
auto test = [](int i) -> std::optional<int> {
switch(i) {
case 1:
case 3:
case 7:
case 9:
return i * 2;
default:
return {};
}
};
auto result = v
| std::views::transform(test)
| std::views::filter([](auto x) { return bool(x); })
| std::views::transform([](auto x){ return *x; })
| std::ranges::to<std::vector>();
bool ok = result == std::vector<int>{6, 14, 18, 2};
VERIFY(ok);
}
constexpr
bool
all_tests()
{
test(42);
int i = 42;
test(&i);
test(std::string_view("test"));
test(std::vector<int>{1, 2, 3, 4});
test(std::optional<int>(42));
test<const int>(42);
range_chain_example();
return true;
}
static_assert(all_tests());
|
