class Nokogiri::XML::Builder

end
xml.awesome # add the "awesome" tag below "some_tag"
# ... Use normal builder methods here ...
Nokogiri::XML::Builder.with(doc.at_css('some_tag')) do |xml|
doc = Nokogiri::XML(File.read('somedoc.xml'))

For example:

given +root+ node.
builder methods. The builder context created will start with the
you have an existing document that you would like to augment with
Create a builder with an existing root object. This is for use when
##

def self.with(root, &block)
  new({}, root, &block)
end