class UserAgent

def self.parse(string)
  if string.nil? || string.strip == ""
    string = DEFAULT_USER_AGENT
  end
  agents = Browsers::Base.new
  while m = string.to_s.match(MATCHER)
    agents << new(m[1], m[2], m[4])
    string = string[m[0].length..-1].strip
  end
  Browsers.extend(agents)
end