debug_stream_variant.hpp

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// -----------------------------------------------------------------------------------------------------
// Copyright (c) 2006-2020, Knut Reinert & Freie Universität Berlin
// Copyright (c) 2016-2020, Knut Reinert & MPI für molekulare Genetik
// This file may be used, modified and/or redistributed under the terms of the 3-clause BSD-License
// shipped with this file and also available at: https://github.com/seqan/seqan3/blob/master/LICENSE.md
// -----------------------------------------------------------------------------------------------------
 
#pragma once
 
#include <variant>
 
#include <seqan3/core/detail/debug_stream_type.hpp>
#include <seqan3/core/type_traits/template_inspection.hpp>
 
namespace seqan3
{
template <typename variant_type, typename char_t>
    requires detail::is_type_specialisation_of_v<remove_cvref_t<variant_type>, std::variant>
inline debug_stream_type<char_t> & operator<<(debug_stream_type<char_t> & s, variant_type && v)
{
    if (!v.valueless_by_exception())
        std::visit([&s] (auto && arg) {s << arg;}, v);
    else
        s << "<VALUELESS_VARIANT>";
    return s;
}
 
 
} // namespace seqan3