SeqAn3 3.4.0
The Modern C++ library for sequence analysis.
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optional.hpp
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1// SPDX-FileCopyrightText: 2006-2025 Knut Reinert & Freie Universität Berlin
2// SPDX-FileCopyrightText: 2016-2025 Knut Reinert & MPI für molekulare Genetik
3// SPDX-License-Identifier: BSD-3-Clause
4
9
10#pragma once
11
12#include <optional>
13
14#include <seqan3/core/debug_stream/debug_stream_type.hpp>
15#include <seqan3/core/detail/template_inspection.hpp>
16#include <seqan3/utility/type_traits/basic.hpp>
17
18namespace seqan3
19{
20
23template <>
24struct optional_printer<std::nullopt_t>
25{
31 template <typename stream_t>
32 constexpr void operator()(stream_t & stream, std::nullopt_t const SEQAN3_DOXYGEN_ONLY(arg)) const
33 {
34 stream << "<VALUELESS_OPTIONAL>";
35 }
36};
37
42template <typename T>
43struct optional_printer<std::optional<T>>
44{
51 template <typename stream_t, typename arg_t>
52 constexpr void operator()(stream_t & stream, arg_t && arg) const
53 {
54 if (arg.has_value())
55 stream << *arg;
56 else
57 stream << "<VALUELESS_OPTIONAL>";
58 }
59};
60
61} // namespace seqan3
basic.hpp
Provides various type traits on generic types.
debug_stream_type.hpp
Provides seqan3::debug_stream and related types.
seqan3
The main SeqAn3 namespace.
Definition aligned_sequence_concept.hpp:26
std
SeqAn specific customisations in the standard namespace.
seqan3::optional_printer< std::nullopt_t >::operator()
constexpr void operator()(stream_t &stream, std::nullopt_t const arg) const
Prints std::nullopt_t to formatted output stream.
Definition optional.hpp:32
seqan3::optional_printer< std::optional< T > >::operator()
constexpr void operator()(stream_t &stream, arg_t &&arg) const
Print the optional to the stream by printing its value or nothing if valueless.
Definition optional.hpp:52
seqan3::optional_printer
Definition default_printer.hpp:40
template_inspection.hpp
Provides type traits for working with templates.
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