feat: grammar::range user-provided RangeRule

#943

Author: alandefreitas

doc/mrdocs.yml

@@ -41,6 +41,8 @@ implementation-defined:
   - 'boost::urls::string_token::*_t'
 exclude-symbols:
   - 'boost::urls::void_t'
+  # any_rule was previously excluded by the detail path rule
+  - 'boost::urls::any_rule'
 
 # Metadata Extraction
 private-bases: false

include/boost/url/grammar/detail/range_rule.hpp

@@ -0,0 +1,95 @@
+//
+// Copyright (c) 2025 Alan de Freitas (vinnie dot falco at gmail dot com)
+//
+// 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)
+//
+// Official repository: https://github.com/boostorg/url
+//
+
+#ifndef BOOST_URL_GRAMMAR_DETAIL_RANGE_RULE_HPP
+#define BOOST_URL_GRAMMAR_DETAIL_RANGE_RULE_HPP
+
+#include <boost/url/detail/config.hpp>
+#include <type_traits>
+#include <utility>
+
+namespace boost {
+namespace urls {
+namespace grammar {
+namespace detail {
+
+template<class RangeRule, bool = std::is_empty<RangeRule>::value>
+class range_base_storage;
+
+template<class RangeRule>
+class range_base_storage<RangeRule, false>
+{
+    RangeRule rule_;
+
+protected:
+    range_base_storage() = default;
+
+    explicit
+    range_base_storage(RangeRule const& rule)
+        : rule_(rule)
+    {
+    }
+
+    explicit
+    range_base_storage(RangeRule&& rule)
+        : rule_(std::move(rule))
+    {
+    }
+
+    RangeRule&
+    rule() noexcept
+    {
+        return rule_;
+    }
+
+    RangeRule const&
+    rule() const noexcept
+    {
+        return rule_;
+    }
+};
+
+template<class RangeRule>
+class range_base_storage<RangeRule, true>
+    : private RangeRule
+{
+protected:
+    range_base_storage() = default;
+
+    explicit
+    range_base_storage(RangeRule const& rule)
+        : RangeRule(rule)
+    {
+    }
+
+    explicit
+    range_base_storage(RangeRule&& rule)
+        : RangeRule(std::move(rule))
+    {
+    }
+
+    RangeRule&
+    rule() noexcept
+    {
+        return *this;
+    }
+
+    RangeRule const&
+    rule() const noexcept
+    {
+        return *this;
+    }
+};
+
+} // detail
+} // grammar
+} // urls
+} // boost
+
+#endif