Module: Nokogiri::ClassResolver

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Included In: `HTML4::Builder`, `HTML4::Document`, `HTML4::DocumentFragment`, `HTML5::Builder`, `HTML5::Document`, `HTML5::DocumentFragment`, `HTML::Builder`, `HTML::Document`, `HTML::DocumentFragment`, `XML::Attr`, `XML::AttributeDecl`, `XML::Builder`, `XML::CDATA`, `XML::CharacterData`, `XML::Comment`, `XML::DTD`, `XML::Document`, `XML::DocumentFragment`, `XML::ElementDecl`, `XML::EntityDecl`, `XML::EntityReference`, `XML::Node`, `XML::ProcessingInstruction`, `XML::Text`, `::NokogiriHtml5::Document`, `::NokogiriXml::DTD`
Defined in:	lib/nokogiri/class_resolver.rb

Overview

Some classes in ::Nokogiri are namespaced as a group, for example Document, DocumentFragment, and Builder.

It’s sometimes necessary to look up the related class, e.g.:

XML::Builder → XML::Document
HTML4::Builder → HTML4::Document
HTML5::Document → HTML5::DocumentFragment

This module is included into those key classes who need to do this.

Constant Summary

VALID_NAMESPACES =

#related_class restricts matching namespaces to those matching this set.

# File 'lib/nokogiri/class_resolver.rb', line 21
```
Set.new(["HTML", "HTML4", "HTML5", "XML"])
```

Instance Method Summary

#related_class(class_name) → Class)

Find a class constant within the.

Instance Method Details

#related_class(class_name) → Class)

Find a class constant within the

Some examples:

Nokogiri::XML::Document.new.related_class("DocumentFragment")
# => Nokogiri::XML::DocumentFragment
Nokogiri::HTML4::Document.new.related_class("DocumentFragment")
# => Nokogiri::HTML4::DocumentFragment

Note this will also work for subclasses that follow the same convention, e.g.:

Loofah::HTML::Document.new.related_class("DocumentFragment")
# => Loofah::HTML::DocumentFragment

And even if it’s a subclass, this will iterate through the superclasses:

class ThisIsATopLevelClass < Nokogiri::HTML4::Builder ; end
ThisIsATopLevelClass.new.related_class("Document")
# => Nokogiri::HTML4::Document

[ GitHub ]

# File 'lib/nokogiri/class_resolver.rb', line 46


def related_class(class_name)
  klass = nil
  inspecting = self.class

  while inspecting
    namespace_path = inspecting.name.split("::")[0..-2]
    inspecting = inspecting.superclass

    next unless VALID_NAMESPACES.include?(namespace_path.last)

    related_class_name = (namespace_path << class_name).join("::")
    klass = begin
      Object.const_get(related_class_name)
    rescue NameError
      nil
    end
    break if klass
  end
  klass
end