donner::css::Specificity Class Reference

A CSS specificity value (id, class, type), as defined in https://www.w3.org/TR/selectors-4/#specificity-rules, which is used during cascading to determine which style takes precedence. More...

#include "donner/css/Specificity.h"

Classes
struct	ABC
	A 3-tuple of integers representing the specificity before modifiers such as the "!important" flag have been applied. More...

Public Member Functions
constexpr	Specificity ()=default
	Default constructor, creates a specificity of (0, 0, 0).
constexpr	Specificity (const ABC &abc)
	Constructs a specificity from a ABC 3-tuple.
	~Specificity ()=default
	Destructor.
	Specificity (const Specificity &other)=default
	Copy constructor.
	Specificity (Specificity &&other) noexcept=default
	Move constructor.
Specificity &	operator= (const Specificity &other)=default
	Assignment operator.
Specificity &	operator= (Specificity &&other) noexcept=default
	Move assignment operator.
auto	operator<=> (const Specificity &other) const
	Spaceship operator.
bool	operator== (const Specificity &other) const
	Equality operator, for gtest.
const ABC &	abc () const
	Gets the 3-tuple of integers.

Static Public Member Functions
static constexpr Specificity	FromABC (uint32_t a, uint32_t b, uint32_t c)
	Creates a specificity from the 3-tuple of integers.
static constexpr Specificity	Important ()
	Creates a specificity for an !important declaration.
static constexpr Specificity	StyleAttribute ()
	Creates a specificity for a style attribute.
static constexpr Specificity	Override ()
	Creates a specificity that overrides any other value, for overriding styles from the C++ API.

Friends
std::ostream &	operator<< (std::ostream &os, const Specificity &obj)
	Ostream output operator.

Detailed Description

A CSS specificity value (id, class, type), as defined in https://www.w3.org/TR/selectors-4/#specificity-rules, which is used during cascading to determine which style takes precedence.

The specificity is a 3-tuple of integers, where the first integer is the most significant, plus a few special values such as "!important" which override.

The 3-tuple is defined as:

• a: The number of ID selectors in the selector.
• b: The number of class selectors, attributes selectors, and pseudo-classes in the selector.
• c: The number of type selectors and pseudo-elements in the selector.

Examples

Selector	Specificity
#id	(1, 0, 0)
.class	(0, 1, 0)
div	(0, 0, 1)
#id.class	(1, 1, 0)
#id.class div	(1, 1, 1)
#id.class > div	(1, 1, 1)
[class=~"class"]	(1, 1, 1)

For example, the selector #id.class has a specificity of (1, 1, 0), while div > p has a specificity of (0, 0, 2).

To construct from a 3-tuple:

const Specificity spec = Specificity::FromABC(1, 2, 3);

To construct from "!important":

const Specificity spec = Specificity::Important();

Member Function Documentation

FromABC()

static constexpr Specificity donner::css::Specificity::FromABC ( uint32_t a, uint32_t b, uint32_t c )

inlinestaticconstexpr

Creates a specificity from the 3-tuple of integers.

Parameters

a	The number of ID selectors in the selector.
b	The number of class selectors, attributes selectors, and pseudo-classes in the selector.
c	The number of type selectors and pseudo-elements in the selector.

Friends And Related Symbol Documentation

operator<<

std::ostream & operator<< ( std::ostream & os, const Specificity & obj )

friend

Ostream output operator.

Example output:

Specificity(1, 2, 3)

or

Specificity(!important)

Parameters

os	Output stream.
obj	Specificity to output.

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

• donner/css/Specificity.h