From b232c5abc00e3df04633105a0599782842d7b2bc Mon Sep 17 00:00:00 2001
From: Nana Sakisaka <1901813+saki7@users.noreply.github.com>
Date: Wed, 10 Sep 2025 10:41:59 +0900
Subject: [PATCH] Modernize `x3::raw`

---
 .../boost/spirit/home/x3/directive/raw.hpp    | 95 ++++++++++++-------
 test/x3/raw.cpp                               |  2 +-
 2 files changed, 63 insertions(+), 34 deletions(-)

diff --git a/include/boost/spirit/home/x3/directive/raw.hpp b/include/boost/spirit/home/x3/directive/raw.hpp
index 2914eb921..ddd66bdb7 100644
--- a/include/boost/spirit/home/x3/directive/raw.hpp
+++ b/include/boost/spirit/home/x3/directive/raw.hpp
@@ -1,5 +1,6 @@
 /*=============================================================================
     Copyright (c) 2014 Joel de Guzman
+    Copyright (c) 2025 Nana Sakisaka
 
     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)
@@ -11,11 +12,20 @@
 #include <boost/spirit/home/x3/core/parser.hpp>
 #include <boost/spirit/home/x3/support/traits/move_to.hpp>
 #include <boost/spirit/home/x3/support/traits/pseudo_attribute.hpp>
-#include <boost/range/iterator_range_core.hpp>
 
-namespace boost { namespace spirit { namespace x3
+#ifndef BOOST_SPIRIT_X3_NO_BOOST_ITERATOR_RANGE
+# pragma message("Use of `boost::iterator_range` is deprecated in X3. #define BOOST_SPIRIT_X3_NO_BOOST_ITERATOR_RANGE")
+# include <boost/range/iterator_range_core.hpp>
+#endif
+
+#include <ranges>
+#include <iterator>
+#include <type_traits>
+#include <utility>
+
+namespace boost::spirit::x3
 {
-    // this is a pseudo attribute type indicating that the parser wants the
+    // Pseudo attribute type indicating that the parser wants the
     // iterator range pointing to the [first, last) matching characters from
     // the input iterators.
     struct raw_attribute_type {};
@@ -23,64 +33,83 @@ namespace boost { namespace spirit { namespace x3
     template <typename Subject>
     struct raw_directive : unary_parser<Subject, raw_directive<Subject>>
     {
-        typedef unary_parser<Subject, raw_directive<Subject> > base_type;
-        typedef raw_attribute_type attribute_type;
-        static bool const handles_container = true;
-        typedef Subject subject_type;
+        using base_type = unary_parser<Subject, raw_directive<Subject>>;
+        using attribute_type = raw_attribute_type;
+        using subject_type = Subject;
 
-        constexpr raw_directive(Subject const& subject)
-          : base_type(subject) {}
+        static constexpr bool handles_container = true;
 
-        template <typename Iterator, typename Context
-            , typename RContext, typename Attribute>
-        bool parse(Iterator& first, Iterator const& last
-          , Context const& context, RContext& rcontext, Attribute& attr) const
+        template <typename SubjectT>
+            requires std::is_constructible_v<Subject, SubjectT>
+        constexpr raw_directive(SubjectT&& subject)
+            noexcept(std::is_nothrow_constructible_v<Subject, SubjectT>)
+            : base_type(std::forward<SubjectT>(subject))
+        {}
+
+        template <std::forward_iterator It, std::sentinel_for<It> Se, typename Context, typename RContext, typename Attribute>
+        [[nodiscard]] constexpr bool
+        parse(It& first, Se const& last, Context const& context, RContext& rcontext, Attribute& attr) const
+            // never noexcept; construction of `std::ranges::subrange` is never noexcept
         {
+            static_assert(Parsable<Subject, It, Se, Context, RContext, unused_type>);
+
             x3::skip_over(first, last, context);
-            Iterator i = first;
-            if (this->subject.parse(i, last, context, rcontext, unused))
+            It local_it = first;
+            if (this->subject.parse(local_it, last, context, rcontext, unused))
             {
-                traits::move_to(first, i, attr);
-                first = i;
+                traits::move_to(first, local_it, attr);
+                first = local_it;
                 return true;
             }
             return false;
         }
 
-        template <typename Iterator, typename Context, typename RContext>
-        bool parse(Iterator& first, Iterator const& last
-          , Context const& context, RContext& rcontext, unused_type) const
+        template <std::forward_iterator It, std::sentinel_for<It> Se, typename Context, typename RContext>
+        [[nodiscard]] constexpr bool
+        parse(It& first, Se const& last, Context const& context, RContext& rcontext, unused_type) const
+            noexcept(is_nothrow_parsable_v<Subject, It, Se, Context, RContext, unused_type>)
         {
             return this->subject.parse(first, last, context, rcontext, unused);
         }
     };
 
-    struct raw_gen
+    namespace detail
     {
-        template <typename Subject>
-        constexpr raw_directive<typename extension::as_parser<Subject>::value_type>
-        operator[](Subject const& subject) const
+        struct raw_gen
         {
-            return { as_parser(subject) };
-        }
-    };
+            template <X3Subject Subject>
+            [[nodiscard]] constexpr raw_directive<as_parser_plain_t<Subject>>
+            operator[](Subject&& subject) const
+                noexcept(is_parser_nothrow_constructible_v<raw_directive<as_parser_plain_t<Subject>>, as_parser_t<Subject>>)
+            {
+                return { as_parser(std::forward<Subject>(subject)) };
+            }
+        };
+    } // detail
 
-    constexpr auto raw = raw_gen{};
+    inline namespace cpos
+    {
+        inline constexpr detail::raw_gen raw{};
+    }
 
     namespace traits
     {
-        template <typename Context, typename Iterator>
-        struct pseudo_attribute<Context, raw_attribute_type, Iterator>
+        template <typename Context, std::forward_iterator It>
+        struct pseudo_attribute<Context, raw_attribute_type, It>
         {
             using attribute_type = raw_attribute_type;
-            using type = boost::iterator_range<Iterator>;
+        #ifdef BOOST_SPIRIT_X3_NO_BOOST_ITERATOR_RANGE
+            using type = std::ranges::subrange<It>;
+        #else
+            using type = boost::iterator_range<It>;
+        #endif
 
-            static type call(Iterator& first, Iterator const& last, attribute_type)
+            [[nodiscard]] static constexpr type call(It& first, std::sentinel_for<It> auto const& last, raw_attribute_type)
             {
                 return { first, last };
             }
         };
     }
-}}}
+} // boost::spirit::x3
 
 #endif
diff --git a/test/x3/raw.cpp b/test/x3/raw.cpp
index eed193f9e..9fe2bc909 100644
--- a/test/x3/raw.cpp
+++ b/test/x3/raw.cpp
@@ -29,7 +29,7 @@ int main()
 {
     using spirit_test::test;
     using spirit_test::test_attr;
-    using namespace boost::spirit::x3::ascii;
+    using namespace boost::spirit::x3::standard;
     using boost::spirit::x3::raw;
     using boost::spirit::x3::eps;
     using boost::spirit::x3::lit;