Function try_handle_some

include/boost/leaf/handle_errors.hpp:536–555

template <class TryBlock, class... H>
BOOST_LEAF_ATTRIBUTE_NODISCARD BOOST_LEAF_CONSTEXPR inline
typename std::decay<decltype(std::declval<TryBlock>()())>::type
try_handle_some( TryBlock && try_block, H && ... h ) noexcept
{
    static_assert(is_result_type<decltype(std::declval<TryBlock>()())>::value, "The return type of the try_block passed to a try_handle_some function must be registered with leaf::is_result_type");
    context_type_from_handlers<H...> ctx;
    auto active_context = activate_context(ctx);
    if( auto r = std::forward<TryBlock>(try_block)() )
        return r;
    else
    {
        detail::unload_result(&r);
        error_id id(r.error());
        ctx.deactivate();
        using R = typename std::decay<decltype(std::declval<TryBlock>()())>::type;
        auto rr = ctx.template handle_error<R>(std::move(id), std::forward<H>(h)..., [&r]()->R { return std::move(r); });
        if( !rr )
            ctx.unload(error_id(rr.error()));
        return rr;
    }
}

template <class TryBlock, class... H>
BOOST_LEAF_CONSTEXPR inline