63e88f80
 Hu Chunming
提交三方库
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#ifndef BOOST_LEAF_TO_VARIANT_HPP_INCLUDED
#define BOOST_LEAF_TO_VARIANT_HPP_INCLUDED
// Copyright 2018-2022 Emil Dotchevski and Reverge Studios, Inc.
// 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)
#if __cplusplus >= 201703L
#include <boost/leaf/config.hpp>
#include <boost/leaf/handle_errors.hpp>
#include <boost/leaf/result.hpp>
#include <variant>
#include <optional>
#include <tuple>
namespace boost { namespace leaf {
template <class... E, class TryBlock>
std::variant<typename std::decay<decltype(std::declval<TryBlock>()().value())>::type,std::tuple<std::optional<E>...>>
to_variant( TryBlock && try_block )
{
static_assert(is_result_type<decltype(std::declval<TryBlock>()())>::value, "The return type of the try_block passed to a to_variant function must be registered with leaf::is_result_type");
using T = typename std::decay<decltype(std::declval<TryBlock>()().value())>::type;
using error_tuple_type = std::tuple<std::optional<E>...>;
using variant_type = std::variant<T, error_tuple_type>;
return try_handle_all(
[&]() -> result<variant_type>
{
if( auto r = std::forward<TryBlock>(try_block)() )
return *std::move(r);
else
return r.error();
},
[]( E const * ... e ) -> variant_type
{
return error_tuple_type { e ? std::optional<E>(*e) : std::optional<E>{}... };
},
[]() -> variant_type
{
return error_tuple_type { };
} );
}
} }
#endif
#endif
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