61 lines
1.3 KiB
C++
61 lines
1.3 KiB
C++
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// Copyright 2020 Peter Dimov
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// Distributed under the Boost Software License, Version 1.0.
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// https://www.boost.org/LICENSE_1_0.txt
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#include <boost/describe.hpp>
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#include <boost/mp11.hpp>
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#include <boost/json.hpp>
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#include <type_traits>
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namespace app
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{
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template<class T> void extract( boost::json::object const & obj, char const * name, T & value )
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{
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value = boost::json::value_to<T>( obj.at( name ) );
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}
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template<class T,
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class D1 = boost::describe::describe_members<T,
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boost::describe::mod_public | boost::describe::mod_protected>,
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class D2 = boost::describe::describe_members<T, boost::describe::mod_private>,
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class En = std::enable_if_t<boost::mp11::mp_empty<D2>::value && !std::is_union<T>::value> >
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T tag_invoke( boost::json::value_to_tag<T> const&, boost::json::value const& v )
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{
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auto const& obj = v.as_object();
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T t{};
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boost::mp11::mp_for_each<D1>([&](auto D){
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extract( obj, D.name, t.*D.pointer );
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});
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return t;
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}
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struct A
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{
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int x;
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int y;
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};
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BOOST_DESCRIBE_STRUCT(A, (), (x, y))
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} // namespace app
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#include <iostream>
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int main()
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{
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boost::json::value jv{ { "x", 1 }, { "y", 2 } };
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std::cout << "jv: " << jv << std::endl;
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auto a = boost::json::value_to<app::A>( jv );
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std::cout << "a: { " << a.x << ", " << a.y << " }" << std::endl;
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}
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