class Regexp::Parser

def interval(target_node, token)
  text = token.text
  mchr = text[text.length-1].chr =~ /[?+]/ ? text[text.length-1].chr : nil
  case mchr
  when '?'
    range_text = text[0...-1]
    mode = :reluctant
  when '+'
    range_text = text[0...-1]
    mode = :possessive
  else
    range_text = text
    mode = :greedy
  end
  range = range_text.gsub(/\{|\}/, '').split(',', 2)
  min = range[0].empty? ? 0 : range[0]
  max = range[1] ? (range[1].empty? ? -1 : range[1]) : min
  target_node.quantify(:interval, text, min.to_i, max.to_i, mode)
end