# File lib/nokogiri.rb, line 55
    def parse string, url = nil, encoding = nil, options = nil
      doc =
        if string =~ /^\s*<[^Hh>]*html/i # Probably html
          Nokogiri::HTML::Document.parse(string, url, encoding, options || XML::ParseOptions::DEFAULT_HTML)
        else
          Nokogiri::XML::Document.parse(string, url, encoding, options || XML::ParseOptions::DEFAULT_XML)
        end
      yield doc if block_given?
      doc
    end