module Raabro::ModuleMethods

def _quantify(parser)
  return nil if parser.is_a?(Symbol) && respond_to?(parser)
    # so that :plus and co can be overriden
  case parser
  when '?', :q, :qmark then [ 0, 1 ]
  when '*', :s, :star then [ 0, 0 ]
  when '+', :p, :plus then [ 1, 0 ]
  when '!' then :bang
  else nil
  end
end