class Hashie::Mash

def method_missing(method_name, *args, &blk)
  return self.[](method_name, &blk) if key?(method_name)
  name, suffix = method_suffix(method_name)
  case suffix
  when '='
    self[name] = args.first
  when '?'
    !!self[name]
  when '!'
    initializing_reader(name)
  when '_'
    underbang_reader(name)
  else
    default(method_name)
  end
end