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 ]
    else nil
  end
end