variant.hpp

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// SPDX-FileCopyrightText: 2006-2025 Knut Reinert & Freie Universität Berlin
// SPDX-FileCopyrightText: 2016-2025 Knut Reinert & MPI für molekulare Genetik
// SPDX-License-Identifier: BSD-3-Clause

 
#pragma once
 
#include <variant>
 
#include <seqan3/core/debug_stream/debug_stream_type.hpp>
#include <seqan3/core/detail/template_inspection.hpp>
#include <seqan3/utility/type_traits/basic.hpp>
 
namespace seqan3
{

template <typename... variant_ts>
struct std_variant_printer<std::variant<variant_ts...>>
{
    template <typename stream_t, typename arg_t>
    constexpr void operator()(stream_t & stream, arg_t && arg) const
    {
        if (!arg.valueless_by_exception())
            std::visit(
                [&stream](auto && elem)
                {
                    stream << elem;
                },
                arg);
        else
            stream << "<VALUELESS_VARIANT>";
    }
};
} // namespace seqan3