module MultiXml

def parser=(new_parser)

* :rexml
* :nokogiri
* :libxml

Supported by default are:
Set the XML parser utilizing a symbol, string, or class. 
def parser=(new_parser)
  case new_parser
  when String, Symbol
    require "multi_xml/parsers/#{new_parser.to_s.downcase}"
    @parser = MultiXml::Parsers.const_get("#{new_parser.to_s.split('_').map{|s| s.capitalize}.join('')}")
  when Class, Module
    @parser = new_parser
  else
    raise "Did not recognize your parser specification. Please specify either a symbol or a class."
  end
end