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Fix char/string related traits for cv-qualified types #77

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Merged
saki7 merged 1 commit into from
Aug 24, 2026
Merged

Fix char/string related traits for cv-qualified types #77

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36 changes: 29 additions & 7 deletions include/iris/string.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -6,18 +6,20 @@
#include <iris/config.hpp> // IWYU pragma: keep

#include <concepts>
#include <string>
#include <string_view>
#include <type_traits>
#include <utility>
#include <string> // IWYU pragma: export
#include <string_view> // IWYU pragma: export

namespace iris {

template<class T>
concept CharLike =
std::same_as<T, char> ||
std::same_as<T, char32_t> ||
std::same_as<T, wchar_t> ||
std::same_as<T, char8_t> ||
std::same_as<T, char16_t>;
std::same_as<std::remove_cv_t<T>, char> ||
std::same_as<std::remove_cv_t<T>, char32_t> ||
std::same_as<std::remove_cv_t<T>, wchar_t> ||
std::same_as<std::remove_cv_t<T>, char8_t> ||
std::same_as<std::remove_cv_t<T>, char16_t>;

template<class T>
concept StringLike =
Expand All @@ -30,6 +32,26 @@ concept StringLike =
template<class T>
concept NotStringLike = !StringLike<T>;


namespace detail {

template<class T>
struct char_type_for_impl
{
using type = decltype(std::basic_string_view{std::declval<T>()})::value_type;
};

template<CharLike CharT>
struct char_type_for_impl<CharT>
{
using type = std::remove_cv_t<CharT>;
};

} // detail

template<class T>
using char_type_for = detail::char_type_for_impl<T>::type;

} // iris

#endif
72 changes: 72 additions & 0 deletions test/string_algo.cpp
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
#include "iris_test.hpp"

#include <iris/string.hpp>
#include <iris/string_algo.hpp>

#include <format>
Expand All @@ -14,6 +15,77 @@ using namespace std::string_view_literals;

// NOLINTBEGIN(readability-container-size-empty)

TEST_CASE("string: type traits")
{
STATIC_CHECK(iris::CharLike<char>);
STATIC_CHECK(iris::CharLike<wchar_t>);
STATIC_CHECK(iris::CharLike<char8_t>);
STATIC_CHECK(iris::CharLike<char16_t>);
STATIC_CHECK(iris::CharLike<char32_t>);

STATIC_CHECK(iris::CharLike<char const>);
STATIC_CHECK(iris::CharLike<char volatile>);
STATIC_CHECK(iris::CharLike<char const volatile>);
STATIC_CHECK(!iris::CharLike<char const&>);
STATIC_CHECK(!iris::CharLike<char&>);

STATIC_CHECK(std::same_as<iris::char_type_for<char>, char>);
STATIC_CHECK(std::same_as<iris::char_type_for<char const>, char>);
STATIC_CHECK(std::same_as<iris::char_type_for<char volatile>, char>);
STATIC_CHECK(std::same_as<iris::char_type_for<char const volatile>, char>);

STATIC_CHECK(std::same_as<iris::char_type_for<char*>, char>);
STATIC_CHECK(std::same_as<iris::char_type_for<char const*>, char>);

#define IRIS_CHECK_STRING_LIKE(CharT, type) \
STATIC_CHECK(iris::StringLike<type>); \
STATIC_CHECK(std::same_as<iris::char_type_for<type>, CharT>);

IRIS_CHECK_STRING_LIKE(char, char const*);
IRIS_CHECK_STRING_LIKE(char, char const* const);
IRIS_CHECK_STRING_LIKE(char, char const*&);
IRIS_CHECK_STRING_LIKE(char, char const* const&);
IRIS_CHECK_STRING_LIKE(char, char const*&&);
IRIS_CHECK_STRING_LIKE(char, char const* const&&);

IRIS_CHECK_STRING_LIKE(char, std::string_view);
IRIS_CHECK_STRING_LIKE(char, std::string_view const);
IRIS_CHECK_STRING_LIKE(char, std::string_view&);
IRIS_CHECK_STRING_LIKE(char, std::string_view const&);
IRIS_CHECK_STRING_LIKE(char, std::string_view&&);
IRIS_CHECK_STRING_LIKE(char, std::string_view const&&);

IRIS_CHECK_STRING_LIKE(char, std::string);
IRIS_CHECK_STRING_LIKE(char, std::string const);
IRIS_CHECK_STRING_LIKE(char, std::string&);
IRIS_CHECK_STRING_LIKE(char, std::string const&);
IRIS_CHECK_STRING_LIKE(char, std::string&&);
IRIS_CHECK_STRING_LIKE(char, std::string const&&);

IRIS_CHECK_STRING_LIKE(char32_t, char32_t const*);
IRIS_CHECK_STRING_LIKE(char32_t, char32_t const* const);
IRIS_CHECK_STRING_LIKE(char32_t, char32_t const*&);
IRIS_CHECK_STRING_LIKE(char32_t, char32_t const* const&);
IRIS_CHECK_STRING_LIKE(char32_t, char32_t const*&&);
IRIS_CHECK_STRING_LIKE(char32_t, char32_t const* const&&);

IRIS_CHECK_STRING_LIKE(char32_t, std::u32string_view);
IRIS_CHECK_STRING_LIKE(char32_t, std::u32string_view const);
IRIS_CHECK_STRING_LIKE(char32_t, std::u32string_view&);
IRIS_CHECK_STRING_LIKE(char32_t, std::u32string_view const&);
IRIS_CHECK_STRING_LIKE(char32_t, std::u32string_view&&);
IRIS_CHECK_STRING_LIKE(char32_t, std::u32string_view const&&);

IRIS_CHECK_STRING_LIKE(char32_t, std::u32string);
IRIS_CHECK_STRING_LIKE(char32_t, std::u32string const);
IRIS_CHECK_STRING_LIKE(char32_t, std::u32string&);
IRIS_CHECK_STRING_LIKE(char32_t, std::u32string const&);
IRIS_CHECK_STRING_LIKE(char32_t, std::u32string&&);
IRIS_CHECK_STRING_LIKE(char32_t, std::u32string const&&);

#undef IRIS_CHECK_STRING_LIKE
}

TEST_CASE("string_algo: trim")
{
#ifdef _MSC_VER
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