整理

include/boost/pfr/core_name.hpp

@@ -0,0 +1,118 @@
+// Copyright (c) 2023 Bela Schaum, X-Ryl669, Denis Mikhailov.
+//
+// Distributed under 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)
+
+
+// Initial implementation by Bela Schaum, https://github.com/schaumb
+// The way to make it union and UB free by X-Ryl669, https://github.com/X-Ryl669
+//
+
+#ifndef BOOST_PFR_CORE_NAME_HPP
+#define BOOST_PFR_CORE_NAME_HPP
+#pragma once
+
+#include <boost/pfr/detail/config.hpp>
+
+#if !defined(BOOST_USE_MODULES) || defined(BOOST_PFR_INTERFACE_UNIT)
+
+#include <boost/pfr/detail/core_name.hpp>
+
+#include <boost/pfr/detail/sequence_tuple.hpp>
+#include <boost/pfr/detail/stdarray.hpp>
+#include <boost/pfr/detail/make_integer_sequence.hpp>
+
+#include <boost/pfr/tuple_size.hpp>
+
+#if !defined(BOOST_PFR_INTERFACE_UNIT)
+#include <cstddef> // for std::size_t
+#endif
+
+/// \file boost/pfr/core_name.hpp
+/// Contains functions \forcedlink{get_name} and \forcedlink{names_as_array} to know which names each field of any \aggregate has.
+///
+/// \fnrefl for details.
+///
+/// \b Synopsis:
+
+namespace boost { namespace pfr {
+
+BOOST_PFR_BEGIN_MODULE_EXPORT
+
+/// \brief Returns name of a field with index `I` in \aggregate `T`.
+///
+/// \b Example:
+/// \code
+///     struct my_struct { int i, short s; };
+///
+///     assert(boost::pfr::get_name<0, my_struct>() == "i");
+///     assert(boost::pfr::get_name<1, my_struct>() == "s");
+/// \endcode
+template <std::size_t I, class T>
+constexpr
+#ifdef BOOST_PFR_DOXYGEN_INVOKED
+std::string_view
+#else
+auto
+#endif
+get_name() noexcept {
+    return detail::get_name<T, I>();
+}
+
+// FIXME: implement this
+// template<class U, class T>
+// constexpr auto get_name() noexcept {
+//     return detail::sequence_tuple::get_by_type_impl<U>( detail::tie_as_names_tuple<T>() );
+// }
+
+/// \brief Creates a `std::array` from names of fields of an \aggregate `T`.
+///
+/// \b Example:
+/// \code
+///     struct my_struct { int i, short s; };
+///     std::array<std::string_view, 2> a = boost::pfr::names_as_array<my_struct>();
+///     assert(a[0] == "i");
+/// \endcode
+template <class T>
+constexpr
+#ifdef BOOST_PFR_DOXYGEN_INVOKED
+std::array<std::string_view, boost::pfr::tuple_size_v<T>>
+#else
+auto
+#endif
+names_as_array() noexcept {
+    return detail::make_stdarray_from_tietuple(
+        detail::tie_as_names_tuple<T>(),
+        detail::make_index_sequence< tuple_size_v<T> >()
+    );
+}
+
+
+/// Calls `func` for each field with its name of a `value`
+///
+/// \param func must have one of the following signatures:
+///     * any_return_type func(std::string_view name, U&& field)                // field of value is perfect forwarded to function
+///     * any_return_type func(std::string_view name, U&& field, std::size_t i)
+///     * any_return_type func(std::string_view name, U&& value, I i)           // Here I is an `std::integral_constant<size_t, field_index>`
+///
+/// \param value To each field of this variable will be the `func` applied.
+///
+/// \b Example:
+/// \code
+///     struct Toto { int a; char c; };
+///     Toto t {5, 'c'};
+///     auto print = [](std::string_view name, const auto& value){ std::cout << "Name: " << name << " Value: " << value << std::endl; };
+///     for_each_field_with_name(t, print);
+/// \endcode
+template <class T, class F>
+constexpr void for_each_field_with_name(T&& value, F&& func) {
+    return boost::pfr::detail::for_each_field_with_name(std::forward<T>(value), std::forward<F>(func));
+}
+
+BOOST_PFR_END_MODULE_EXPORT
+
+}} // namespace boost::pfr
+
+#endif  // #if !defined(BOOST_USE_MODULES) || defined(BOOST_PFR_INTERFACE_UNIT)
+
+#endif // BOOST_PFR_CORE_NAME_HPP