hext::NthChildMatch Class Reference

Matches HTML nodes having a certain position within their parent HTML element. More...

Inheritance diagram for hext::NthChildMatch:

Collaboration diagram for hext::NthChildMatch:

Public Types
enum	Option { First = 1 << 1 , Last = 1 << 2 , OfType = 1 << 3 }
	NthChildMatch's options. More...

Public Member Functions
	NthChildMatch (int step, int shift, Option options=Option::First) noexcept
	Constructs an NthChildMatch with the pattern <step * n + shift>. More...
	NthChildMatch (std::pair< int, int > step_and_shift, Option options=Option::First) noexcept
	Constructs an NthChildMatch with the pattern <step * n + shift>, where step and shift is given as a std::pair. More...
bool	matches (const GumboNode *node) const noexcept override
	Returns true if HTML node matches pattern <step * n + shift>. More...
Public Member Functions inherited from hext::Cloneable< NthChildMatch, Match >
virtual std::unique_ptr< Match >	clone () const override
	Clones objects of template type Derived and returns an owning pointer to the newly allocated Base. More...
Public Member Functions inherited from hext::Match
	Match () noexcept=default
	Match (const Match &)=default
	Match (Match &&) noexcept=default
Match &	operator= (const Match &)=default
Match &	operator= (Match &&) noexcept=default
virtual	~Match () noexcept=default

Detailed Description

Matches HTML nodes having a certain position within their parent HTML element.

The intent is to mimic the following CSS pseudo-classes: nth-child, nth-of-type, nth-last-of-type, first-of-type, last-of-type, first-child, last-child, nth-last-child, nth-last-of-type

See https://developer.mozilla.org/en-US/docs/Web/CSS/%3Anth-child for a detailed explanation.

Example:

// Assume first, second, third are children of the following <ul> element:
// <ul><li>1</li><li>2</li><li>3</li></ul>
const GumboNode * first  = ...;
const GumboNode * second = ...;
const GumboNode * third  = ...;
 
NthChildMatch m_even(2, 0); // :nth-child(2n)
NthChildMatch m_odd (2, 1); // :nth-child(2n+1)
 
assert(!m_even.matches(first));
assert( m_even.matches(second));
assert(!m_even.matches(third));
 
assert( m_odd.matches(first));
assert(!m_odd.matches(second));
assert( m_odd.matches(third));

last-of-type Example:

// Assume first, second, third are children of the following <a> element:
// <a>
//   <b>1</b>
//   <u>2</u>
//   <b>3</b>
// </a>
const GumboNode * first  = ...;
const GumboNode * second = ...;
const GumboNode * third  = ...;
 
NthChildMatch m_last_of_type(
  0,                        // no repetition
  1,                        // last element
  NthChildMatch::Last |     // count following siblings and
    NthChildMatch::OfType   // only count elements with
                            // same tag.
);
 
assert(!m_last_of_type.matches(first));
assert( m_last_of_type.matches(second));
assert( m_last_of_type.matches(third));

Definition at line 88 of file NthChildMatch.h.

Member Enumeration Documentation

Option

enum hext::NthChildMatch::Option

NthChildMatch's options.

Enumerator
First	Count preceding siblings (:nth-child).
Last	Count following siblings (:nth-last-child).
OfType	Only count siblings of the same type (:nth-of-type).

Definition at line 92 of file NthChildMatch.h.

Constructor & Destructor Documentation

NthChildMatch() [1/2]

hext::NthChildMatch::NthChildMatch ( int  step, int  shift, Option  options = Option::First  )

noexcept

Constructs an NthChildMatch with the pattern <step * n + shift>.

Parameters

step	The step of the pattern.
shift	The shift of the pattern.
options	See NthChildMatch::Option. Default: Count any preceding HTML element.

NthChildMatch() [2/2]

hext::NthChildMatch::NthChildMatch ( std::pair< int, int >  step_and_shift, Option  options = Option::First  )

explicitnoexcept

Constructs an NthChildMatch with the pattern <step * n + shift>, where step and shift is given as a std::pair.

Parameters

step_and_shift	The step and shift of the pattern.
options	See NthChildMatch::Option. Default: Count any preceding HTML element.

Member Function Documentation

matches()

bool hext::NthChildMatch::matches ( const GumboNode *  node ) const

overridevirtualnoexcept

Returns true if HTML node matches pattern <step * n + shift>.

Parameters

node	A pointer to a GumboNode.

Implements hext::Match.

---

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

• hext/NthChildMatch.h