Class modeling a symbol in Clingo. More...

#include <symbol.hh>

Public Member Functions
	Symbol ()=default
	Default constructor, creates a symbol holding number zero.

	~Symbol ()
	The destructor releases the symbol.

	Symbol (Symbol const &other) noexcept
	The copy constructor acquires the symbol.

auto	operator= (Symbol const &other) noexcept -> Symbol &
	The copy assignment acquires the symbol and releases the old one.

	Symbol (Symbol &&other) noexcept
	The move constructor transfers ownership of the symbol.

auto	operator= (Symbol &&other) noexcept -> Symbol &
	The move assignment transfers ownership and releases the old one.

	Symbol (clingo_symbol_t rep, bool acquire)
	Construct a symbol from its C API representation.

auto	number () const -> int
	Get the numeric value of the symbol if it is a number.

auto	name () const -> std::string_view
	Get the name of the symbol if it is a function.

auto	string () const -> std::string_view
	Get the string value of the symbol if it is a string.

auto	is_positive () const -> bool
	Check whether a function or number symbol is positive.

auto	is_negative () const -> bool
	Check whether a function or number symbol is negative.

auto	arguments () const -> SymbolSpan
	Get the arguments of a function or tuple symbol.

auto	type () const -> SymbolType
	Get the type of the symbol.

auto	to_string () const -> std::string
	Get a string representation of the symbol.

auto	signature () const -> std::optional< std::tuple< std::string_view, size_t, bool > >
	Get the signature of the symbol if it is a function.

auto	match (std::string_view name, size_t arity, bool positive=true) const -> bool
	Match the symbol against a function signature.

auto	match (size_t arity) const -> bool
	Match the symbol against a tuple signature.

auto	hash () const noexcept -> size_t
	Compute a hash value for the symbol.

Friends
auto	c_cast (Symbol const &sym) -> clingo_symbol_t const &
	Cast the symbol to its C API representation.

auto	c_cast (Symbol const sym) -> clingo_symbol_t const
	Cast the symbol to its C API representation.

auto	operator== (Symbol const &a, Symbol const &b) noexcept -> bool
	Compare two symbols for equality.

auto	operator<=> (Symbol const &a, Symbol const &b) noexcept -> std::strong_ordering
	Compare two symbols.

auto	operator<< (std::ostream &out, Symbol const &sym) -> std::ostream &
	Output the symbol to a stream.

Detailed Description

Class modeling a symbol in Clingo.

Symbols are immutable and can be created from numbers, strings, functions, tuples, or parsed terms.

They are totally ordered and support hashing also provding a specialization for std::hash.

Symbols are reference counted modeling value semantics. They are stored in library objects and should all be released before the library is. Failing to do so won't lead to crashed but prevents release of the underlying symbol store.

Constructor & Destructor Documentation

◆ Symbol() [1/3]

Clingo::Symbol::Symbol ( Symbol const & other )

inlinenoexcept

The copy constructor acquires the symbol.

Parameters

other the symbol to copy

◆ Symbol() [2/3]

Clingo::Symbol::Symbol ( Symbol && other )

inlinenoexcept

The move constructor transfers ownership of the symbol.

Parameters

other the symbol to move

◆ Symbol() [3/3]

Clingo::Symbol::Symbol	(	clingo_symbol_t	rep,
		bool	acquire
	)

inlineexplicit

Construct a symbol from its C API representation.

For internal use.

Parameters

rep	the C API representation of the symbol
acquire	whether to acquire the symbol

Member Function Documentation

◆ arguments()

auto Clingo::Symbol::arguments ( ) const -> SymbolSpan

inline

Get the arguments of a function or tuple symbol.

Returns: a span of symbols representing the arguments

◆ hash()

auto Clingo::Symbol::hash ( ) const -> size_t

inlinenoexcept

Compute a hash value for the symbol.

The hash value is entended for usage in hash tables.

Returns: a hash value for the symbol

◆ is_negative()

auto Clingo::Symbol::is_negative ( ) const -> bool

inline

Check whether a function or number symbol is negative.

Returns: whether the symbol is negative

◆ is_positive()

auto Clingo::Symbol::is_positive ( ) const -> bool

inline

Check whether a function or number symbol is positive.

Returns: whether the symbol is positive

◆ match() [1/2]

auto Clingo::Symbol::match ( size_t arity ) const -> bool

inline

Match the symbol against a tuple signature.

Parameters

arity the number of arguments of the tuple

Returns: whether the symbol matches the tuple signature

◆ match() [2/2]

auto Clingo::Symbol::match	(	std::string_view	name,
		size_t	arity,
		bool	positive = `true`
	)		const -> bool

inline

Match the symbol against a function signature.

Parameters

name	the name of the function
arity	the number of arguments of the function
positive	whether the function is positive

Returns: whether the symbol matches the function signature

◆ name()

auto Clingo::Symbol::name ( ) const -> std::string_view

inline

Get the name of the symbol if it is a function.

Returns: the name of the symbol

◆ number()

auto Clingo::Symbol::number ( ) const -> int

inline

Get the numeric value of the symbol if it is a number.

Returns: the numeric value of the symbol

◆ operator=() [1/2]

auto Clingo::Symbol::operator= ( Symbol && other ) -> Symbol &

inlinenoexcept

The move assignment transfers ownership and releases the old one.

Parameters

other the symbol to move

Returns: a reference to this symbol

◆ operator=() [2/2]

auto Clingo::Symbol::operator= ( Symbol const & other ) -> Symbol &

inlinenoexcept

The copy assignment acquires the symbol and releases the old one.

Parameters

other the symbol to copy

Returns: a reference to this symbol

◆ signature()

auto Clingo::Symbol::signature ( ) const -> std::optional<std::tuple<std::string_view, size_t, bool>>

inline

Get the signature of the symbol if it is a function.

The result is empty if the symbol is not a function.

Returns: an optional name arity positivity tuple

◆ string()

auto Clingo::Symbol::string ( ) const -> std::string_view

inline

Get the string value of the symbol if it is a string.

Returns: the string value of the symbol

◆ to_string()

auto Clingo::Symbol::to_string ( ) const -> std::string

inline

Get a string representation of the symbol.

The string representation adheres to clingo's input language and is parsable by clingo.

Returns: a string representation of the symbol

◆ type()

auto Clingo::Symbol::type ( ) const -> SymbolType

inline

Get the type of the symbol.

Returns: the type of the symbol

Friends And Related Symbol Documentation

◆ c_cast [1/2]

auto c_cast ( Symbol const & sym ) -> clingo_symbol_t const &

friend

Cast the symbol to its C API representation.

Parameters

sym	the symbol to cast

Returns: the C API representation of the symbol

◆ c_cast [2/2]

auto c_cast ( Symbol const * sym ) -> clingo_symbol_t const *

friend

Cast the symbol to its C API representation.

Parameters

sym	the symbol to cast

Returns: the C API representation of the symbol

◆ operator<<

auto operator<<	(	std::ostream &	out,
		Symbol const &	sym
	)		-> std::ostream &

friend

Output the symbol to a stream.

Parameters

out	the output stream
sym	the symbol to output

Returns: the output stream

◆ operator<=>

auto operator<=>	(	Symbol const &	a,
		Symbol const &	b
	)		-> std::strong_ordering

friend

Compare two symbols.

Parameters

a	the first symbol to compare
b	the second symbol to compare

Returns: the result of the comparison

◆ operator==

auto operator==	(	Symbol const &	a,
		Symbol const &	b
	)		-> bool

friend

Compare two symbols for equality.

Parameters

a	the first symbol to compare
b	the second symbol to compare

Returns: whether the symbols are equal

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

clingo/symbol.hh

Public Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

◆ Symbol() [1/3]

◆ Symbol() [2/3]

◆ Symbol() [3/3]

Member Function Documentation

◆ arguments()

◆ hash()

◆ is_negative()

◆ is_positive()

◆ match() [1/2]

◆ match() [2/2]

◆ name()

◆ number()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ signature()

◆ string()

◆ to_string()

◆ type()

Friends And Related Symbol Documentation

◆ c_cast [1/2]

◆ c_cast [2/2]

◆ operator<<

◆ operator<=>

◆ operator==