optional.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 <optional>
 
#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 <>
struct optional_printer<std::nullopt_t>
{
    template <typename stream_t>
    constexpr void operator()(stream_t & stream, std::nullopt_t const SEQAN3_DOXYGEN_ONLY(arg)) const
    {
        stream << "<VALUELESS_OPTIONAL>";
    }
};
 
template <typename T>
struct optional_printer<std::optional<T>>
{
    template <typename stream_t, typename arg_t>
    constexpr void operator()(stream_t & stream, arg_t && arg) const
    {
        if (arg.has_value())
            stream << *arg;
        else
            stream << "<VALUELESS_OPTIONAL>";
    }
};
 
} // namespace seqan3