class Chronic::Numerizer

def andition(string)
  sc = StringScanner.new(string)
  while sc.scan_until(/<num>(\d+)( | and )<num>(\d+)(?=[^\w]|$)/i)
    if sc[2] =~ /and/ || sc[1].size > sc[3].size
      string[(sc.pos - sc.matched_size)..(sc.pos-1)] = '<num>' + (sc[1].to_i + sc[3].to_i).to_s
      sc.reset
    end
  end
end