donner::css::ComponentValue Struct Reference

A CSS component value, which is either a token, or a parsed function or block. More...

#include "donner/css/ComponentValue.h"

Public Types
using	Type = std::variant<Token, Function, SimpleBlock>
	The type of the component value, which is either a base Token or a logical group of tokens, Function or SimpleBlock.

Public Member Functions
	ComponentValue (Type &&value)
	Construct a new ComponentValue object, taking ownership of a Token.
	~ComponentValue ()
	Destructor.
	ComponentValue (const ComponentValue &)=default
	Copy constructor.
ComponentValue &	operator= (const ComponentValue &)=default
	Move constructor.
	ComponentValue (ComponentValue &&) noexcept=default
	Move assignment operator.
ComponentValue &	operator= (ComponentValue &&) noexcept=default
	Copy assignment operator.
bool	operator== (const ComponentValue &other) const
	Equality operator.
template<typename T >
bool	is () const
	Check if the component value is of a given type.
template<typename T >
bool	isToken () const
	Shorthand for checking if this component value holds a specific token.
template<typename T >
const T *	tryGetToken () const
	Get the inner token value as a pointer, if the component value is a token and matches the requested type, or nullptr.
template<typename T >
T &	get () &
	Get the component value as a reference.
template<typename T >
const T &	get () const &
	Get the component value as a const-reference.
template<typename T >
T &&	get () &&
	Get the component value as an rvalue-reference for move semantics.
parser::FileOffset	sourceOffset () const
	Get the offset of this component value in the original source.

Public Attributes
Type	value
	The actual value of the component value.

Friends
std::ostream &	operator<< (std::ostream &os, const ComponentValue &component)
	Output a human-readable representation of the component value to a stream.

Detailed Description

A CSS component value, which is either a token, or a parsed function or block.

This is the second level of parsing, after Token. A Token is a single lexical unit, and ComponentValue groups those into logical function and block groups, as well as wrapping standalone Token.

ComponentValue is the base component traversed when parsing CSS into logical blocks, such as Selector and donner::svg::Property.

Constructor & Destructor Documentation

ComponentValue()

donner::css::ComponentValue::ComponentValue

(

ComponentValue::Type &&

value

)

Construct a new ComponentValue object, taking ownership of a Token.

Parameters

value

Token to construct from.

Member Function Documentation

get() [1/3]

template<typename T >

T & donner::css::ComponentValue::get ( ) &

inline

Get the component value as a reference.

Example usage:

SimpleBlock& block = component.get<SimpleBlock>();
block.values.push_back(componentValue);

Template Parameters

T	Type to get, one of Type.

Precondition

The component must be of the given type, i.e. is<T>() must be true.

get() [2/3]

template<typename T >

T && donner::css::ComponentValue::get ( ) &&

inline

Get the component value as an rvalue-reference for move semantics.

Example usage:

SimpleBlock block = std::move(component.get<SimpleBlock>());

Template Parameters

T	Type to get, one of Type.

Precondition

The component must be of the given type, i.e. is<T>() must be true.

get() [3/3]

template<typename T >

const T & donner::css::ComponentValue::get ( ) const &

inline

Get the component value as a const-reference.

Example usage:

const SimpleBlock& block = component.get<SimpleBlock>();

Template Parameters

T	Type to get, one of Type.

Precondition

The component must be of the given type, i.e. is<T>() must be true.

is()

template<typename T >

bool donner::css::ComponentValue::is ( ) const

inline

Check if the component value is of a given type.

For example:

if (component.is<SimpleBlock>()) {
  // ...
}

Template Parameters

T	Type to check, one of Type.

Returns

True if the component value is of type T.

isToken()

template<typename T >

bool donner::css::ComponentValue::isToken ( ) const

inline

Shorthand for checking if this component value holds a specific token.

For example:

if (component.isToken<Token::Percentage>()) {

Which is equivalent to component.is<Token>() && component.get<Token>().is<Token::Percentage>().

Template Parameters

T	Token type to check, which must be within the Token::TokenValue list.

sourceOffset()

parser::FileOffset donner::css::ComponentValue::sourceOffset ( ) const

inline

Get the offset of this component value in the original source.

For Function and SimpleBlock, returns the offset of the group opening token.

tryGetToken()

template<typename T >

const T * donner::css::ComponentValue::tryGetToken ( ) const

inline

Get the inner token value as a pointer, if the component value is a token and matches the requested type, or nullptr.

See also Token::tryGet().

Example:

if (const Token::Percentage* percentage = component.tryGetToken<Token::Percentage>()) {
  // ...
}

Template Parameters

T	Token type to check, which must be within the Token::TokenValue list.

Friends And Related Symbol Documentation

operator<<

std::ostream & operator<< ( std::ostream & os, const ComponentValue & component )

friend

Output a human-readable representation of the component value to a stream.

Parameters

os	Output stream.
component	Component value to output.

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

• donner/css/ComponentValue.h
• donner/css/ComponentValue.cc