From e12919329667013f82cd7653ecc7c2ba349dbe0d Mon Sep 17 00:00:00 2001
From: Zach Laine <whatwasthataddress@gmail.com>
Date: Sun, 3 Mar 2024 16:54:23 -0600
Subject: [PATCH] Now that the library requires C++17, use std::any instead of
 any_copyable.

---
 include/boost/parser/parser.hpp     |  8 ++--
 include/boost/parser/parser_fwd.hpp | 64 +----------------------------
 test/parser.cpp                     |  6 +--
 test/parser_api.cpp                 |  6 +--
 4 files changed, 8 insertions(+), 76 deletions(-)

diff --git a/include/boost/parser/parser.hpp b/include/boost/parser/parser.hpp
index 3a31b428..b3402822 100644
--- a/include/boost/parser/parser.hpp
+++ b/include/boost/parser/parser.hpp
@@ -938,16 +938,16 @@ namespace boost { namespace parser {
             using trie_t = text::trie<std::vector<char32_t>, T>;
             symbol_table_tries_t & symbol_table_tries =
                 *context.symbol_table_tries_;
-            any_copyable & a = symbol_table_tries[(void *)&symbol_parser];
-            if (a.empty()) {
+            std::any & a = symbol_table_tries[(void *)&symbol_parser];
+            if (!a.has_value()) {
                 a = trie_t{};
-                trie_t & trie = a.cast<trie_t>();
+                trie_t & trie = *std::any_cast<trie_t>(&a);
                 for (auto const & e : symbol_parser.initial_elements()) {
                     trie.insert(e.first | text::as_utf32, e.second);
                 }
                 return trie;
             } else {
-                return a.cast<trie_t>();
+                return *std::any_cast<trie_t>(&a);
             }
         }
 
diff --git a/include/boost/parser/parser_fwd.hpp b/include/boost/parser/parser_fwd.hpp
index ee0708eb..fcfda326 100644
--- a/include/boost/parser/parser_fwd.hpp
+++ b/include/boost/parser/parser_fwd.hpp
@@ -9,6 +9,7 @@
 #include <boost/parser/config.hpp>
 #include <boost/parser/error_handling_fwd.hpp>
 
+#include <any>
 #include <cstdint>
 #include <map>
 #include <memory>
@@ -70,69 +71,8 @@ namespace boost { namespace parser {
             in_apply_parser = 1 << 3
         };
 
-        struct any_copyable
-        {
-            template<
-                typename T,
-                typename Enable = std::enable_if_t<!std::is_reference_v<T>>>
-            any_copyable(T && v) :
-                impl_(new holder<std::decay_t<T>>(std::move(v)))
-            {}
-            template<typename T>
-            any_copyable(T const & v) : impl_(new holder<T>(v))
-            {}
-
-            any_copyable() = default;
-            any_copyable(any_copyable const & other)
-            {
-                if (other.impl_)
-                    impl_ = other.impl_->clone();
-            }
-            any_copyable & operator=(any_copyable const & other)
-            {
-                any_copyable temp(other);
-                swap(temp);
-                return *this;
-            }
-            any_copyable(any_copyable &&) = default;
-            any_copyable & operator=(any_copyable &&) = default;
-
-            bool empty() const { return impl_.get() == nullptr; }
-
-            template<typename T>
-            T & cast() const
-            {
-                BOOST_PARSER_DEBUG_ASSERT(impl_);
-                BOOST_PARSER_DEBUG_ASSERT(dynamic_cast<holder<T> *>(impl_.get()));
-                return static_cast<holder<T> *>(impl_.get())->value_;
-            }
-
-            void swap(any_copyable & other) { std::swap(impl_, other.impl_); }
-
-        private:
-            struct holder_base
-            {
-                virtual ~holder_base() {}
-                virtual std::unique_ptr<holder_base> clone() const = 0;
-            };
-            template<typename T>
-            struct holder : holder_base
-            {
-                holder(T && v) : value_(std::move(v)) {}
-                holder(T const & v) : value_(v) {}
-                virtual ~holder() {}
-                virtual std::unique_ptr<holder_base> clone() const
-                {
-                    return std::unique_ptr<holder_base>(new holder<T>{value_});
-                }
-                T value_;
-            };
-
-            std::unique_ptr<holder_base> impl_;
-        };
-
         using symbol_table_tries_t =
-            std::map<void *, any_copyable, std::less<void *>>;
+            std::map<void *, std::any, std::less<void *>>;
 
         template<
             bool DoTrace,
diff --git a/test/parser.cpp b/test/parser.cpp
index f5c8803d..39b44eb6 100644
--- a/test/parser.cpp
+++ b/test/parser.cpp
@@ -2044,11 +2044,7 @@ TEST(parser, combined_seq_and_or)
 
         {
             std::string str = "abc";
-            tuple<
-                boost::parser::detail::any_copyable,
-                boost::parser::detail::any_copyable,
-                boost::parser::detail::any_copyable>
-                chars;
+            tuple<std::any, std::any, std::any> chars;
             EXPECT_TRUE(parse(str, parser, chars));
         }
 
diff --git a/test/parser_api.cpp b/test/parser_api.cpp
index 0b975087..a9cff820 100644
--- a/test/parser_api.cpp
+++ b/test/parser_api.cpp
@@ -1816,11 +1816,7 @@ TEST(parser, combined_seq_and_or)
 
         {
             char const * str = "abc";
-            tuple<
-                boost::parser::detail::any_copyable,
-                boost::parser::detail::any_copyable,
-                boost::parser::detail::any_copyable>
-                chars;
+            tuple<std::any, std::any, std::any> chars;
             EXPECT_TRUE(parse(str, parser, chars));
         }