seqan3::record< field_types, field_ids > Struct Template Reference

The class template that file records are based on; behaves like a std::tuple. More...

#include <seqan3/io/record.hpp>

Inheritance diagram for seqan3::record< field_types, field_ids >:

Public Types
using	base_type = detail::transfer_template_args_onto_t< field_types, std::tuple >
	A specialisation of std::tuple.

Public Member Functions
void	clear () noexcept(noexcept(std::apply(expander, std::declval< record & >().as_base())))
	Clears containers that provide .clear() and (re-)initialises all other elements with = {}.
Constructors, destructor and assignment
	record ()=default
	Defaulted.
	record (record const &)=default
	Defaulted.
record &	operator= (record const &)=default
	Defaulted.
	record (record &&)=default
	Defaulted.
record &	operator= (record &&)=default
	Defaulted.
	~record ()=default
	Defaulted.

Private Types
template<field f>
using	field_constant = std::integral_constant< field, f >
	A type alias for std::integral_constant.

Private Member Functions
base_type &	as_base () noexcept
	Returns the tuple as the underlying std::tuple type.

Static Private Member Functions
template<typename t >
static constexpr void	clear_element (t &v) noexcept(noexcept(std::declval< t & >()=t{}))
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
template<typename t > requires requires (t & v) { v.clear(); }
static constexpr void	clear_element (t &v) noexcept(noexcept(v.clear()))
	Auxiliary functions for clear().
template<field f, typename tuple_t >
static decltype(auto)	get_impl (field_constant< f >, tuple_t &&record_as_tuple)
	This is basically the seqan3::get<f>(static_cast<tuple>(record)) implementation.

Static Private Attributes
static constexpr auto	expander
	A lambda function that expands a pack and calls clear_element on every argument in the pack.

Additional Inherited Members
Related Symbols inherited from tuple_like
size_t	tuple_size_v
	A unary type trait that holds the number of elements in the tuple.
	tuple_elment_t
	A transformation trait that holds the type of elements in the tuple.
auto &&	get (type &&val)
	Return the i-th element of the tuple.

Detailed Description

template<typename field_types, typename field_ids>
struct seqan3::record< field_types, field_ids >

The class template that file records are based on; behaves like a std::tuple.

Template Parameters

field_types	The types of the fields in this record as a seqan3::type_list.
field_ids	A seqan3::fields type with seqan3::field IDs corresponding to field_types.

This class template behaves just like a std::tuple, with the exception that it provides an additional get-interface that takes a seqan3::field identifier. The traditional get interfaces (via index and via type) are also supported, but discouraged, because accessing via seqan3::field is unambiguous and better readable.

Example

For input files this template is specialised automatically and provided by the file via its record_type member. For output files you my define it locally and pass instances of this to the output file's push_back().

This is how it works:

// SPDX-FileCopyrightText: 2006-2025 Knut Reinert & Freie Universität Berlin
// SPDX-FileCopyrightText: 2016-2025 Knut Reinert & MPI für molekulare Genetik
// SPDX-License-Identifier: CC0-1.0
 
#include <string>
#include <vector>
 
#include <seqan3/alphabet/nucleotide/dna4.hpp>
#include <seqan3/alphabet/quality/phred42.hpp>
#include <seqan3/io/record.hpp>
#include <seqan3/utility/type_list/type_list.hpp>
 
int main()
{
    using namespace seqan3::literals;
 
    // The order of the types below represent a mapping between the type and the key.
    using types = seqan3::type_list<seqan3::dna4_vector, std::string, std::vector<seqan3::phred42>>;
    using types_as_ids = seqan3::fields<seqan3::field::seq, seqan3::field::id, seqan3::field::qual>;
    using record_type = seqan3::record<types, types_as_ids>;
    // record_type now mimics std::tuple<std::string, dna4_vector, std::vector<phred42>>,
    // the order also depends on selected_ids
 
    record_type my_record{};
    std::get<1>(my_record) = "the most important sequence in the database";            // access via index
    std::get<std::string>(my_record) = "the least important sequence in the database"; // access via type
}

Member Data Documentation

expander

template<typename field_types , typename field_ids >

constexpr auto seqan3::record< field_types, field_ids >::expander

staticconstexprprivate

Initial value:

= [](auto &... args)
    {
        (clear_element(args), ...);
    }

A lambda function that expands a pack and calls clear_element on every argument in the pack.

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The documentation for this struct was generated from the following file:

• record.hpp