**WIP DO NOT MERGE IT**: Add automatic serialization support for boost::hana::Struct

include/trial/protocol/json/serialization/boost/hana.hpp

@@ -0,0 +1,90 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (C) 2021 Vinícius dos Santos Oliveira
+//
+// 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)
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef TRIAL_PROTOCOL_JSON_SERIALIZATION_BOOST_HANA_HPP
+#define TRIAL_PROTOCOL_JSON_SERIALIZATION_BOOST_HANA_HPP
+
+#include <trial/protocol/json/serialization/serialization.hpp>
+#include <boost/hana.hpp>
+#include <trial/protocol/json/token.hpp>
+#include <trial/protocol/json/partial/skip.hpp>
+
+namespace trial
+{
+namespace protocol
+{
+namespace serialization
+{
+
+template <typename CharT, typename Value>
+struct save_overloader<json::basic_oarchive<CharT>,
+                       Value,
+                       std::enable_if_t<boost::hana::Struct<Value>::value>>
+{
+    static void save(json::basic_oarchive<CharT>& ar,
+                     const Value& data,
+                     const unsigned int /*protocol_version*/)
+    {
+        using string_view = core::detail::basic_string_view<CharT>;
+
+        ar.template save<json::token::begin_object>();
+        boost::hana::for_each(data, [&ar](auto member) {
+            auto key = boost::hana::first(member);
+            ar.save(string_view(key.c_str(), boost::hana::size(key)));
+            // TODO: what if subvalue uses old reflection infra? then it
+            // requires us to write the necessary framing (begin_array and
+            // end_array)
+            ar << boost::hana::second(member);
+        });
+        ar.template save<json::token::end_object>();
+    }
+};
+
+template <typename CharT, typename Value>
+struct load_overloader<json::basic_iarchive<CharT>,
+                       Value,
+                       std::enable_if_t<boost::hana::Struct<Value>::value>>
+{
+    static void load(json::basic_iarchive<CharT>& ar,
+                     Value& data,
+                     const unsigned int /*protocol_version*/)
+    {
+        ar.template load<json::token::begin_object>();
+        for (;;) {
+            if (ar.symbol() == json::token::symbol::end_object) {
+                ar.template load<json::token::end_object>();
+                break;
+            }
+
+            // skip key
+            {
+                auto r = ar.reader();
+                json::partial::skip(r);
+                ar.reader(std::move(r));
+            }
+            // skip value
+            {
+                auto r = ar.reader();
+                json::partial::skip(r);
+                ar.reader(std::move(r));
+            }
+
+            // TODO: actually decode stuff
+            //ar >> x;
+        }
+        ar.template load<json::token::end_object>();
+    }
+};
+
+} // namespace serialization
+} // namespace protocol
+} // namespace trial
+
+#endif // TRIAL_PROTOCOL_JSON_SERIALIZATION_BOOST_HANA_HPP

test/json/CMakeLists.txt

@@ -19,6 +19,7 @@ trial_add_test(json_writer_suite writer_suite.cpp)
 trial_add_test(json_iarchive_suite iarchive_suite.cpp)
 trial_add_test(json_oarchive_suite oarchive_suite.cpp)
 trial_add_test(json_partial_skip_suite skip_suite.cpp)
+trial_add_test(hana_reflection_suite hana_reflection_suite.cpp)
 
 # Tree processing
 trial_add_test(json_parse_suite parse_suite.cpp)

test/json/hana_reflection_suite.cpp

@@ -0,0 +1,70 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (C) 2021 Vinícius dos Santos Oliveira
+//
+// 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)
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include <sstream>
+#include <trial/protocol/buffer/ostream.hpp>
+#include <trial/protocol/json/serialization/boost/hana.hpp>
+#include <trial/protocol/core/detail/lightweight_test.hpp>
+
+using namespace trial::protocol;
+
+//-----------------------------------------------------------------------------
+// Basic types
+//-----------------------------------------------------------------------------
+
+struct Foobar {
+    BOOST_HANA_DEFINE_STRUCT(Foobar,
+        (int, foo),
+        (int, bar),
+        (int, baz)
+    );
+};
+
+namespace basic_suite
+{
+
+void test_oarchive()
+{
+    std::ostringstream result;
+    json::oarchive ar(result);
+    Foobar value{5, 10, 0};
+    ar << value;
+    TRIAL_PROTOCOL_TEST_EQUAL(result.str(), "{\"foo\":5,\"bar\":10,\"baz\":0}");
+}
+
+void test_iarchive()
+{
+    const char input[] = "{\"foo\":5,\"bar\":10,\"baz\":0}";
+    json::iarchive in(input);
+    Foobar value{1, 2, 3};
+    TRIAL_PROTOCOL_TEST_NO_THROW(in >> value);
+    TRIAL_PROTOCOL_TEST_EQUAL(value.foo, 5);
+    TRIAL_PROTOCOL_TEST_EQUAL(value.bar, 10);
+    TRIAL_PROTOCOL_TEST_EQUAL(value.baz, 0);
+}
+
+void run()
+{
+    test_oarchive();
+    test_iarchive();
+}
+
+} // namespace basic_suite
+
+//-----------------------------------------------------------------------------
+// main
+//-----------------------------------------------------------------------------
+
+int main()
+{
+    basic_suite::run();
+
+    return boost::report_errors();
+}