A combined alphabet that can hold values of either of its alternatives. More...

#include <seqan3/alphabet/composite/alphabet_variant.hpp>

Inheritance diagram for seqan3::alphabet_variant< alternative_types >:

Public Member Functions
Constructors, destructor and assignment
constexpr	alphabet_variant () noexcept=default
	Defaulted.

constexpr	alphabet_variant (alphabet_variant const &) noexcept=default
	Defaulted.

constexpr	alphabet_variant (alphabet_variant &&) noexcept=default
	Defaulted.

constexpr alphabet_variant &	operator= (alphabet_variant const &) noexcept=default
	Defaulted.

constexpr alphabet_variant &	operator= (alphabet_variant &&) noexcept=default
	Defaulted.

	~alphabet_variant () noexcept=default
	Defaulted.

template<typename alternative_t >
constexpr	alphabet_variant (alternative_t const alternative) noexcept
	Construction via the value of an alternative. More...

template<typename indirect_alternative_t >
constexpr	alphabet_variant (indirect_alternative_t const rhs) noexcept
	Constructor for arguments implicitly convertible to an alternative. More...

template<typename indirect_alternative_t >
constexpr	alphabet_variant (indirect_alternative_t const rhs) noexcept
	Constructor for arguments explicitly (but not implicitly) convertible to an alternative. More...

template<typename indirect_alternative_t >
constexpr alphabet_variant &	operator= (indirect_alternative_t const &rhs) noexcept
	Assignment for arguments assignable to an alternative. More...

Conversion (by index)
template<size_t index>
constexpr bool	is_alternative () const noexcept
	Whether the variant alphabet currently holds a value of the given alternative. More...

template<size_t index>
constexpr auto	convert_to () const
	Convert to the specified alphabet (throws if is_alternative() would be false). More...

template<size_t index>
constexpr auto	convert_unsafely_to () const noexcept
	Convert to the specified alphabet (undefined behaviour if is_alternative() would be false). More...

Conversion (by type)
template<typename alternative_t >
constexpr bool	is_alternative () const noexcept
	Whether the variant alphabet currently holds a value of the given alternative. More...

template<typename alternative_t >
constexpr alternative_t	convert_to () const
	Convert to the specified alphabet (throws if is_alternative() would be false). More...

template<typename alternative_t >
constexpr alternative_t	convert_unsafely_to () const noexcept
	Convert to the specified alphabet (undefined behaviour if is_alternative() would be false). More...

Read functions
constexpr char_type	to_char () const noexcept
	Return the letter as a character of char_type. More...

constexpr rank_type	to_rank () const noexcept
	Return the letter's numeric value (rank in the alphabet). More...

Write functions
constexpr alphabet_variant< alternative_types... > &	assign_char (char_type const c) noexcept
	Assign from a character, implicitly converts invalid characters. More...

constexpr alphabet_variant< alternative_types... > &	assign_rank (rank_type const c) noexcept
	Assign from a numeric value. More...

Static Public Member Functions
static constexpr bool	char_is_valid (char_type const chr) noexcept
	Validate whether a character is valid in the combined alphabet.

template<typename alternative_t >
static constexpr bool	holds_alternative () noexcept
	Returns true if alternative_t is one of the given alternative types. More...

Static Public Attributes
static constexpr detail::min_viable_uint_t< size >	alphabet_size
	The size of the alphabet, i.e. the number of different values it can take. More...

Protected Types
Member types
using	char_type = std::conditional_t< std::same_as< char, void >, char, char >
	The char representation; conditional needed to make semi alphabet definitions legal. More...

using	rank_type = detail::min_viable_uint_t< size - 1 >
	The type of the alphabet when represented as a number (e.g. via to_rank()). More...

Private Types
using	alternatives = meta::list< alternative_types... >
	A meta::list of the types of each alternative in the composite.

using	base_t = alphabet_base< alphabet_variant< alternative_types... >,(static_cast< size_t >(alphabet_size< alternative_types >)+...), char >
	The base type.

using	seqan3_recursive_required_types = list_traits::concat< seqan3_required_types, detail::transformation_trait_or_t< detail::recursive_required_types< alternative_types >, type_list<> >... >
	Expose the recursive alternative types to concept checks in metaprogramming.

using	seqan3_required_types = type_list< alternative_types... >
	Expose the alternative types to concept checks in metaprogramming.

Private Member Functions
template<size_t index, bool throws>
constexpr auto	convert_impl () const noexcept(!throws) -> meta::at_c< alternatives, index >
	Implementation function for convert_to() and convert_unsafely_to(). More...

Static Private Member Functions
template<size_t index, typename alternative_t >
static constexpr rank_type	rank_by_index_ (alternative_t const &alternative) noexcept
	Converts an object of one of the given alternatives into the internal representation. More...

template<typename alternative_t >
static constexpr rank_type	rank_by_type_ (alternative_t const &alternative) noexcept
	Converts an object of one of the given alternatives into the internal representation. More...

Private Attributes
friend	base_t
	Befriend the base type.

rank_type	rank
	The value of the alphabet letter is stored as the rank.

Static Private Attributes
static constexpr std::array< rank_type, detail::size_in_values_v< char_type > >	char_to_rank
	Compile-time generated lookup table which maps the char to rank. More...

static constexpr std::array< rank_type, sizeof...(alternative_types)+1 >	partial_sum_sizes
	Compile-time generated lookup table which contains the partial sum up to the position of each alternative. More...

static constexpr std::array< char_type, alphabet_size >	rank_to_char
	Compile-time generated lookup table which maps the rank to char. More...

Friends
Comparison operators (against indirect alternatives)
Defines comparison against types that are not subject to implicit construction/conversion but are comparable against alternatives, e.g. `alphabet_variant<seqan3::rna4, seqan3::gap>` vs `alphabet_variant<seqan3::dna4, seqan3::gap>`. Only (in-)equality comparison is defined as reasoning about order of variants is inherently difficult.
template<typename alphabet_variant_t , typename indirect_alternative_type >
constexpr friend auto	operator== (alphabet_variant_t const lhs, indirect_alternative_type const rhs) noexcept -> std::enable_if_t< detail::variant_comparison_guard< alphabet_variant_t, indirect_alternative_type, false, alternative_types... >, bool >
	(In-)Equality comparison against types comparable with alternatives but not convertible to the variant. More...

template<typename alphabet_variant_t , typename indirect_alternative_type >
constexpr friend auto	operator!= (alphabet_variant_t const lhs, indirect_alternative_type const rhs) noexcept -> std::enable_if_t< detail::variant_comparison_guard< alphabet_variant_t, indirect_alternative_type, false, alternative_types... >, bool >
	(In-)Equality comparison against types comparable with alternatives but not convertible to the variant. More...

template<typename alphabet_variant_t , typename indirect_alternative_type , typename = void>
constexpr friend auto	operator== (indirect_alternative_type const lhs, alphabet_variant_t const rhs) noexcept -> std::enable_if_t< detail::variant_comparison_guard< alphabet_variant_t, indirect_alternative_type, true, alternative_types... >, bool >
	(In-)Equality comparison against types comparable with alternatives but not convertible to the variant. More...

template<typename alphabet_variant_t , typename indirect_alternative_type , typename = void>
constexpr friend auto	operator!= (indirect_alternative_type const lhs, alphabet_variant_t const rhs) noexcept -> std::enable_if_t< detail::variant_comparison_guard< alphabet_variant_t, indirect_alternative_type, true, alternative_types... >, bool >
	(In-)Equality comparison against types comparable with alternatives but not convertible to the variant. More...

Related Functions
(Note that these are not member functions.)
Generic serialisation functions for all seqan3::semialphabet
All types that satisfy seqan3::semialphabet can be serialised via Cereal.
template<cereal_output_archive archive_t, semialphabet alphabet_t>
alphabet_rank_t< alphabet_t >	save_minimal (archive_t const &, alphabet_t const &l)
	Save an alphabet letter to stream. More...

Detailed Description

template<typename ... alternative_types>
class seqan3::alphabet_variant< alternative_types >

A combined alphabet that can hold values of either of its alternatives.

Template Parameters

...alternative_types Types of possible values (at least 2); all must model seqan3::detail::writable_constexpr_alphabet, std::regular and be unique.

The alphabet_variant represents the union of two or more alternative alphabets (e.g. the four letter DNA alternative + the gap alternative). It behaves similar to a variant or std::variant, but it preserves the seqan3::alphabet.

Short description:

combines multiple different alphabets in an "either-or"-fashion;
is itself a seqan3::alphabet;
its alphabet size is the sum of the individual sizes;
default initialises to the the first alternative's default (no empty state like std::variant);
constructible, assignable and (in-)equality-comparable with each alternative type and also all types that these are constructible/assignable/equality-comparable with;
only convertible to its alternatives through the member function convert_to() (which can throw!)

Example

#include <seqan3/alphabet/composite/alphabet_variant.hpp>
#include <seqan3/alphabet/gap/gap.hpp>
#include <seqan3/alphabet/nucleotide/all.hpp>
 
int main()
{
    using seqan3::operator""_dna5;
    using seqan3::operator""_rna5;
 
    seqan3::alphabet_variant<seqan3::dna5, seqan3::gap> letter{};          // implicitly 'A'_dna5
    seqan3::alphabet_variant<seqan3::dna5, seqan3::gap> letter2{'C'_dna5}; // constructed from alternative (== 'C'_dna5)
    seqan3::alphabet_variant<seqan3::dna5, seqan3::gap> letter3{'U'_rna5}; // constructed from type that alternative is constructible from (== 'T'_dna5)
 
    letter2.assign_char('T');                       // == 'T'_dna5
    letter2.assign_char('-');                       // == gap{}
    letter2.assign_char('K');                       // unknown characters map to the default/unknown
                                                    // character of the first alternative type (== 'N'_dna5)
 
    letter2 = seqan3::gap{};                        // assigned from alternative (== gap{})
    letter2 = 'U'_rna5;                             // assigned from type that alternative is assignable from (== 'T'_dna5)
 
    seqan3::dna5 letter4 = letter2.convert_to<seqan3::dna5>();
}

The `char` representation of an alphabet_variant

Part of the seqan3::alphabet concept requires that the alphabet_variant provides a char representation in addition to the rank representation. For an object of seqan3::alphabet_variant, the to_char() member function will always return the same character as if invoked on the respective alternative. In contrast, the assign_char() member function might be ambiguous between the alternative alphabets in a variant.

For example, assigning a '!' to seqan3::dna15 resolves to an object of rank 8 with char representation 'N' while assigning '!' to seqan3::gap always resolves to rank 0, the gap symbol itself ('-'_gap). We tackle this ambiguousness by defaulting unknown characters to the representation of the first alternative (e.g. ‘alphabet_variant<dna15, gap>{}.assign_char(’!')resolves to rank 8, representingN`_dna15).

On the other hand, two alternative alphabets might have the same char representation (e.g if you combine dna4 with dna5, 'A', 'C', 'G' and 'T' are ambiguous). We tackle this ambiguousness by always choosing the first valid char representation (e.g. ‘alphabet_variant<dna4, dna5>{}.assign_char('A’)resolves to rank 0, representing anA`_dna4).

To explicitly assign via the character representation of a specific alphabet, assign to that type first and then assign to the variant, e.g.

#include <seqan3/alphabet/composite/alphabet_variant.hpp>
#include <seqan3/alphabet/nucleotide/all.hpp>
 
int main()
{
    using seqan3::operator""_dna5;
 
    seqan3::alphabet_variant<seqan3::dna4, seqan3::dna5> var;
    var.assign_char('A');             // will be in the "dna4-state"
    var = 'A'_dna5;                   // will be in the "dna5-state"
}

Member Typedef Documentation

◆ char_type

using seqan3::alphabet_base< alphabet_variant< alternative_types... > , size, char >::char_type = std::conditional_t<std::same_as<char , void>, char, char >

protectedinherited

The char representation; conditional needed to make semi alphabet definitions legal.

We need a return type for seqan3::alphabet_base::to_char and seqan3::alphabet_base::assign_char other than void to make these in-class definitions valid when char_t is void.

This entity is stable. Since version 3.1.

◆ rank_type

using seqan3::alphabet_base< alphabet_variant< alternative_types... > , size, char >::rank_type = detail::min_viable_uint_t<size - 1>

protectedinherited

The type of the alphabet when represented as a number (e.g. via to_rank()).

This entity is stable. Since version 3.1.

Constructor & Destructor Documentation

◆ alphabet_variant() [1/3]

template<typename ... alternative_types>

template<typename alternative_t >

constexpr seqan3::alphabet_variant< alternative_types >::alphabet_variant ( alternative_t const alternative )

inlineconstexprnoexcept

Construction via the value of an alternative.

Template Parameters

alternative_t One of the alternative types.

Parameters

alternative The value of a alternative that should be assigned.

#include <seqan3/alphabet/composite/alphabet_variant.hpp>
#include <seqan3/alphabet/gap/gap.hpp>
#include <seqan3/alphabet/nucleotide/all.hpp>
 
int main()
{
    using seqan3::operator""_dna4;
 
    seqan3::alphabet_variant<seqan3::dna4, seqan3::gap> letter1{'C'_dna4}; // or
    seqan3::alphabet_variant<seqan3::dna4, seqan3::gap> letter2 = seqan3::gap{};
}

◆ alphabet_variant() [2/3]

template<typename ... alternative_types>

template<typename indirect_alternative_t >

constexpr seqan3::alphabet_variant< alternative_types >::alphabet_variant ( indirect_alternative_t const rhs )

inlineconstexprnoexcept

Constructor for arguments implicitly convertible to an alternative.

Template Parameters

indirect_alternative_t A type that is implicitly convertible to an alternative type.

Parameters

rhs	The value that should be assigned.

This constructor is preferred over the explicit version.

Example

#include <seqan3/alphabet/composite/alphabet_variant.hpp>
#include <seqan3/alphabet/gap/gap.hpp>
#include <seqan3/alphabet/nucleotide/all.hpp>
 
int main()
{
    using seqan3::operator""_rna4;
 
    seqan3::alphabet_variant<seqan3::dna4, seqan3::gap> letter1{'C'_rna4};
    seqan3::alphabet_variant<seqan3::dna4, seqan3::gap> letter2 = 'C'_rna4;
}

seqan3::dna4 and seqan3::rna4 are implicitly convertible to each other so the variant accepts either.
Construction via {} considers implicit and explicit conversions.
Construction via = considers only implicit conversions (but that is sufficient here).

◆ alphabet_variant() [3/3]

template<typename ... alternative_types>

template<typename indirect_alternative_t >

constexpr seqan3::alphabet_variant< alternative_types >::alphabet_variant ( indirect_alternative_t const rhs )

inlineexplicitconstexprnoexcept

Constructor for arguments explicitly (but not implicitly) convertible to an alternative.

Template Parameters

indirect_alternative_t A type that is explicitly (but not implicitly) convertible to an alternative type.

Parameters

rhs	The value that should be assigned.

Example

#include <seqan3/alphabet/composite/alphabet_variant.hpp>
#include <seqan3/alphabet/gap/gap.hpp>
#include <seqan3/alphabet/nucleotide/all.hpp>
 
int main()
{
    using seqan3::operator""_dna5;
 
    // possible:
    seqan3::alphabet_variant<seqan3::dna4, seqan3::gap> letter1{'C'_dna5};
    // not possible:
    // seqan3::alphabet_variant<seqan3::dna4, seqan3::gap> letter2 = 'C'_dna5;
}

seqan3::dna4 and seqan3::dna5 are not implicitly convertible to each other, only explicitly.
Construction via {} considers implicit and explicit conversions so this works.
Construction via = considers only implicit conversions so it does not work.

Member Function Documentation

◆ assign_char()

constexpr alphabet_variant< alternative_types... > & seqan3::alphabet_base< alphabet_variant< alternative_types... > , size, char >::assign_char ( char_type const c )

inlineconstexprnoexceptinherited

Assign from a character, implicitly converts invalid characters.

Parameters

c	The character to be assigned.

Provides an implementation for seqan3::assign_char_to, required to model seqan3::alphabet.

Complexity

Constant.

Exceptions

Guaranteed not to throw.

This entity is stable. Since version 3.1.

◆ assign_rank()

constexpr alphabet_variant< alternative_types... > & seqan3::alphabet_base< alphabet_variant< alternative_types... > , size, char >::assign_rank ( rank_type const c )

inlineconstexprnoexceptinherited

Assign from a numeric value.

Parameters

c	The rank to be assigned.

Provides an implementation for seqan3::assign_rank_to, required to model seqan3::semialphabet.

Complexity

Constant.

Exceptions

Guaranteed not to throw.

This entity is stable. Since version 3.1.

◆ convert_impl()

template<typename ... alternative_types>

template<size_t index, bool throws>

constexpr auto seqan3::alphabet_variant< alternative_types >::convert_impl ( ) const -> meta::at_c<alternatives, index>

inlineconstexprprivatenoexcept

Implementation function for convert_to() and convert_unsafely_to().

Template Parameters

index	Index of the alternative to convert to.
throws	Whether to perform checks (and throw) or not.

◆ convert_to() [1/2]

template<typename ... alternative_types>

template<size_t index>

constexpr auto seqan3::alphabet_variant< alternative_types >::convert_to ( ) const

inlineconstexpr

Convert to the specified alphabet (throws if is_alternative() would be false).

Template Parameters

index Index of the alternative to check for.

Exceptions

std::bad_variant_access If the variant_alphabet currently holds the value of a different alternative.

◆ convert_to() [2/2]

template<typename ... alternative_types>

template<typename alternative_t >

constexpr alternative_t seqan3::alphabet_variant< alternative_types >::convert_to ( ) const

inlineconstexpr

Convert to the specified alphabet (throws if is_alternative() would be false).

Template Parameters

alternative_t The type of the alternative that you wish to check for.

Exceptions

std::bad_variant_access If the variant_alphabet currently holds the value of a different alternative.

◆ convert_unsafely_to() [1/2]

template<typename ... alternative_types>

template<size_t index>

constexpr auto seqan3::alphabet_variant< alternative_types >::convert_unsafely_to ( ) const

inlineconstexprnoexcept

Convert to the specified alphabet (undefined behaviour if is_alternative() would be false).

Template Parameters

index Index of the alternative to check for.

◆ convert_unsafely_to() [2/2]

template<typename ... alternative_types>

template<typename alternative_t >

constexpr alternative_t seqan3::alphabet_variant< alternative_types >::convert_unsafely_to ( ) const

inlineconstexprnoexcept

Convert to the specified alphabet (undefined behaviour if is_alternative() would be false).

Template Parameters

alternative_t The type of the alternative that you wish to check for.

◆ holds_alternative()

template<typename ... alternative_types>

template<typename alternative_t >

static constexpr bool seqan3::alphabet_variant< alternative_types >::holds_alternative ( )

inlinestaticconstexprnoexcept

Returns true if alternative_t is one of the given alternative types.

Template Parameters

alternative_t The type to check.

#include <seqan3/alphabet/composite/alphabet_variant.hpp>
#include <seqan3/alphabet/gap/gap.hpp>
#include <seqan3/alphabet/nucleotide/all.hpp>
#include <gtest/gtest.h>
 
int main()
{
    using variant_t = seqan3::alphabet_variant<seqan3::dna5, seqan3::gap>;
 
    static_assert(variant_t::holds_alternative<seqan3::dna5>(), "dna5 is an alternative of variant_t");
    static_assert(!variant_t::holds_alternative<seqan3::dna4>(), "dna4 is not an alternative of variant_t");
    static_assert(variant_t::holds_alternative<seqan3::gap>(), "gap is an alternative of variant_t");
}

◆ is_alternative() [1/2]

template<typename ... alternative_types>

template<size_t index>

constexpr bool seqan3::alphabet_variant< alternative_types >::is_alternative ( ) const

inlineconstexprnoexcept

Whether the variant alphabet currently holds a value of the given alternative.

Template Parameters

index Index of the alternative to check for.

◆ is_alternative() [2/2]

template<typename ... alternative_types>

template<typename alternative_t >

constexpr bool seqan3::alphabet_variant< alternative_types >::is_alternative ( ) const

inlineconstexprnoexcept

Whether the variant alphabet currently holds a value of the given alternative.

Template Parameters

alternative_t The type of the alternative that you wish to check for.

◆ operator=()

template<typename ... alternative_types>

template<typename indirect_alternative_t >

constexpr alphabet_variant& seqan3::alphabet_variant< alternative_types >::operator= ( indirect_alternative_t const & rhs )

inlineconstexprnoexcept

Assignment for arguments assignable to an alternative.

Template Parameters

indirect_alternative_t A type that one of the alternatives is assignable from.

Parameters

rhs	The value of an alternative.

Most assignments happen through implicit conversion and the default assignment operator. This constructor is for the rest.

◆ rank_by_index_()

template<typename ... alternative_types>

template<size_t index, typename alternative_t >

static constexpr rank_type seqan3::alphabet_variant< alternative_types >::rank_by_index_ ( alternative_t const & alternative )

inlinestaticconstexprprivatenoexcept

Converts an object of one of the given alternatives into the internal representation.

Template Parameters

index	The position of `alternative_t` in the template pack `alternative_types`.
alternative_t	One of the alternative types.

Parameters

alternative The value of a alternative.

◆ rank_by_type_()

template<typename ... alternative_types>

template<typename alternative_t >

static constexpr rank_type seqan3::alphabet_variant< alternative_types >::rank_by_type_ ( alternative_t const & alternative )

inlinestaticconstexprprivatenoexcept

Converts an object of one of the given alternatives into the internal representation.

Finds the index of alternative_t in the given types.

Template Parameters

alternative_t One of the alternative types.

Parameters

alternative The value of a alternative.

◆ to_char()

constexpr char_type seqan3::alphabet_base< alphabet_variant< alternative_types... > , size, char >::to_char ( ) const

inlineconstexprnoexceptinherited

Return the letter as a character of char_type.

Provides an implementation for seqan3::to_char, required to model seqan3::alphabet.

Complexity

Constant.

Exceptions

Guaranteed not to throw.

This entity is stable. Since version 3.1.

◆ to_rank()

constexpr rank_type seqan3::alphabet_base< alphabet_variant< alternative_types... > , size, char >::to_rank ( ) const

inlineconstexprnoexceptinherited

Return the letter's numeric value (rank in the alphabet).

Provides an implementation for seqan3::to_rank, required to model seqan3::semialphabet.

Complexity

Constant.

Exceptions

Guaranteed not to throw.

This entity is stable. Since version 3.1.

Friends And Related Function Documentation

◆ operator!= [1/2]

template<typename ... alternative_types>

template<typename alphabet_variant_t , typename indirect_alternative_type >

constexpr friend auto operator!=	(	alphabet_variant_t const	lhs,
		indirect_alternative_type const	rhs
	)		-> std::enable_if_t<detail::variant_comparison_guard<alphabet_variant_t, indirect_alternative_type, false, alternative_types...>, bool>

friend

(In-)Equality comparison against types comparable with alternatives but not convertible to the variant.

Template Parameters

alphabet_variant_t	The type of the variant; given as template parameter to prevent conversion.
indirect_alternative_type	Must be comparable with an alternative's type.

Parameters

lhs	Left-hand-side of comparison.
rhs	Right-hand-side of comparison.

Returns: true or false.

To determine (in-)equality, it is first deduced which alternative the argument is comparable with. It is then checked if the variant currently is in that alternative's state and if yes whether the values compare to true; else false is returned.

◆ operator!= [2/2]

template<typename ... alternative_types>

template<typename alphabet_variant_t , typename indirect_alternative_type , typename = void>

constexpr friend auto operator!=	(	indirect_alternative_type const	lhs,
		alphabet_variant_t const	rhs
	)		-> std::enable_if_t<detail::variant_comparison_guard<alphabet_variant_t, indirect_alternative_type, true, alternative_types...>, bool>

friend

(In-)Equality comparison against types comparable with alternatives but not convertible to the variant.

Template Parameters

alphabet_variant_t	The type of the variant; given as template parameter to prevent conversion.
indirect_alternative_type	Must be comparable with an alternative's type.

Parameters

lhs	Left-hand-side of comparison.
rhs	Right-hand-side of comparison.

Returns: true or false.

To determine (in-)equality, it is first deduced which alternative the argument is comparable with. It is then checked if the variant currently is in that alternative's state and if yes whether the values compare to true; else false is returned.

◆ operator== [1/2]

template<typename ... alternative_types>

template<typename alphabet_variant_t , typename indirect_alternative_type >

constexpr friend auto operator==	(	alphabet_variant_t const	lhs,
		indirect_alternative_type const	rhs
	)		-> std::enable_if_t<detail::variant_comparison_guard<alphabet_variant_t, indirect_alternative_type, false, alternative_types...>, bool>

friend

(In-)Equality comparison against types comparable with alternatives but not convertible to the variant.

Template Parameters

alphabet_variant_t	The type of the variant; given as template parameter to prevent conversion.
indirect_alternative_type	Must be comparable with an alternative's type.

Parameters

lhs	Left-hand-side of comparison.
rhs	Right-hand-side of comparison.

Returns: true or false.

To determine (in-)equality, it is first deduced which alternative the argument is comparable with. It is then checked if the variant currently is in that alternative's state and if yes whether the values compare to true; else false is returned.

◆ operator== [2/2]

template<typename ... alternative_types>

template<typename alphabet_variant_t , typename indirect_alternative_type , typename = void>

constexpr friend auto operator==	(	indirect_alternative_type const	lhs,
		alphabet_variant_t const	rhs
	)		-> std::enable_if_t<detail::variant_comparison_guard<alphabet_variant_t, indirect_alternative_type, true, alternative_types...>, bool>

friend

(In-)Equality comparison against types comparable with alternatives but not convertible to the variant.

Template Parameters

alphabet_variant_t	The type of the variant; given as template parameter to prevent conversion.
indirect_alternative_type	Must be comparable with an alternative's type.

Parameters

lhs	Left-hand-side of comparison.
rhs	Right-hand-side of comparison.

Returns: true or false.

To determine (in-)equality, it is first deduced which alternative the argument is comparable with. It is then checked if the variant currently is in that alternative's state and if yes whether the values compare to true; else false is returned.

◆ save_minimal()

template<cereal_output_archive archive_t, semialphabet alphabet_t>

alphabet_rank_t< alphabet_t > save_minimal	(	archive_t const &	,
		alphabet_t const &	l
	)

Template Parameters

archive_t	Must satisfy seqan3::cereal_output_archive.
alphabet_t	Type of l; must satisfy seqan3::semialphabet.

Parameters

l	The alphabet letter.

Delegates to seqan3::to_rank.

Attention: These functions are never called directly, see the Alphabet module on how to use serialisation.

This entity is stable. Since version 3.1.

Member Data Documentation

◆ alphabet_size

constexpr detail::min_viable_uint_t<size> seqan3::alphabet_base< alphabet_variant< alternative_types... > , size, char >::alphabet_size

staticconstexprinherited

The size of the alphabet, i.e. the number of different values it can take.

This entity is stable. Since version 3.1.

◆ char_to_rank

template<typename ... alternative_types>

constexpr std::array<rank_type, detail::size_in_values_v<char_type> > seqan3::alphabet_variant< alternative_types >::char_to_rank

staticconstexprprivate

Compile-time generated lookup table which maps the char to rank.

An map generated at compile time where the key is the char of one of the alternatives and the value is the corresponding rank over all alternatives (by conflict will default to the first).

◆ partial_sum_sizes

template<typename ... alternative_types>

constexpr std::array<rank_type, sizeof...(alternative_types) + 1> seqan3::alphabet_variant< alternative_types >::partial_sum_sizes

staticconstexprprivate

Initial value:

= []() constexpr
    {
        constexpr size_t N = sizeof...(alternative_types) + 1;
 
        std::array<rank_type, N> partial_sum{0, seqan3::alphabet_size<alternative_types>...};
        for (size_t i = 1u; i < N; ++i)
            partial_sum[i] += partial_sum[i-1];
 
        return partial_sum;
    }()

Compile-time generated lookup table which contains the partial sum up to the position of each alternative.

An array which contains the prefix sum over all alternative_types::alphabet_size's.

◆ rank_to_char

template<typename ... alternative_types>

constexpr std::array<char_type, alphabet_size> seqan3::alphabet_variant< alternative_types >::rank_to_char

staticconstexprprivate

Initial value:

= []() constexpr
    {
        
        
        
        auto assign_rank_to_char = [](auto alternative, size_t rank) constexpr
        {
            return seqan3::to_char(seqan3::assign_rank_to(rank, alternative));
        };
 
        auto assign_value_to_char = [assign_rank_to_char] (auto alternative, auto & value_to_char, auto & value) constexpr
        {
            using alternative_t = std::decay_t<decltype(alternative)>;
            for (size_t i = 0u; i < seqan3::alphabet_size<alternative_t>; ++i, ++value)
                value_to_char[value] = assign_rank_to_char(alternative, i);
        };
 
        unsigned value = 0u;
        std::array<char_type, alphabet_size> value_to_char{};
 
        
        
        
        
        ((assign_value_to_char(alternative_types{}, value_to_char, value)),...);
 
        return value_to_char;
    }()

Compile-time generated lookup table which maps the rank to char.

A map generated at compile time where the key is the rank of the variant of all alternatives and the value is the corresponding char of that rank and alternative.

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

seqan3/alphabet/composite/alphabet_variant.hpp

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Types

Private Types

Private Member Functions

Static Private Member Functions

Private Attributes

Static Private Attributes

Friends

Related Functions

Detailed Description

template<typename ... alternative_types> class seqan3::alphabet_variant< alternative_types >

Example

The char representation of an alphabet_variant

Member Typedef Documentation

◆ char_type

◆ rank_type

Constructor & Destructor Documentation

◆ alphabet_variant() [1/3]

◆ alphabet_variant() [2/3]

Example

◆ alphabet_variant() [3/3]

Example

Member Function Documentation

◆ assign_char()

Complexity

Exceptions

◆ assign_rank()

Complexity

Exceptions

◆ convert_impl()

◆ convert_to() [1/2]

◆ convert_to() [2/2]

◆ convert_unsafely_to() [1/2]

◆ convert_unsafely_to() [2/2]

◆ holds_alternative()

◆ is_alternative() [1/2]

◆ is_alternative() [2/2]

◆ operator=()

◆ rank_by_index_()

◆ rank_by_type_()

◆ to_char()

Complexity

Exceptions

◆ to_rank()

Complexity

Exceptions

Friends And Related Function Documentation

◆ operator!= [1/2]

◆ operator!= [2/2]

◆ operator== [1/2]

◆ operator== [2/2]

◆ save_minimal()

Member Data Documentation

◆ alphabet_size

◆ char_to_rank

◆ partial_sum_sizes

◆ rank_to_char

template<typename ... alternative_types>
class seqan3::alphabet_variant< alternative_types >

The `char` representation of an alphabet_variant