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Replace polymorphic lambdas with function objects for C++11

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This commit is contained in:
Peter Dimov
2022-10-18 06:29:57 +03:00
parent 67a12199e6
commit 1f8c4a1900
1 changed files with 42 additions and 19 deletions
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61
include/boost/variant2/variant.hpp
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@ -2449,16 +2449,52 @@ template<> struct is_null_like< variant2::monostate, void >: std::true_type
namespace variant2
{
namespace detail
{
struct tag_invoke_L1
{
boost::json::value& v;
template<class T> void operator()( T const& t ) const
{
boost::json::value_from( t, v );
}
};
} // namespace detail
template<class... T>
void tag_invoke( boost::json::value_from_tag const&, boost::json::value& v, variant<T...> const & w )
{
visit( [&](auto const& t){
boost::json::value_from( t, v );
}, w );
visit( detail::tag_invoke_L1{ v }, w );
}
namespace detail
{
template<class V> struct tag_invoke_L2
{
boost::json::value const& v;
typename boost::json::result_for<V, boost::json::value>::type& r;
template<class I> void operator()( I i ) const
{
if( !r )
{
using Ti = mp11::mp_at_c<V, i>;
auto r2 = boost::json::try_value_to<Ti>( v );
if( r2 )
{
r.emplace( in_place_index_t<i>{}, *r2 );
}
}
}
};
} // namespace detail
template<class... T>
typename boost::json::result_for<variant<T...>, boost::json::value>::type
tag_invoke( boost::json::try_value_to_tag<variant<T...>> const&, boost::json::value const& v )
@ -2466,20 +2502,7 @@ template<class... T>
static constexpr boost::source_location loc = BOOST_CURRENT_LOCATION;
auto r = boost::json::result_from_errno< variant<T...> >( EINVAL, &loc );
mp11::mp_for_each<mp11::mp_iota_c<sizeof...(T)>>( [&](auto I){
if( !r )
{
using Ti = mp11::mp_at_c<variant<T...>, I>;
auto r2 = boost::json::try_value_to<Ti>( v );
if( r2 )
{
r.emplace( in_place_index<I>, *r2 );
}
}
});
mp11::mp_for_each<mp11::mp_iota_c<sizeof...(T)>>( detail::tag_invoke_L2< variant<T...> >{ v, r } );
return r;
}