class Nokogiri::CSS::Parser

def _reduce_49(val, _values, result) 

def _reduce_49(val, _values, result)
                    # 5n, -5n, 10n-1
      n = val[1]
      if n[0, 2] == 'n-'
        val[1] = 'n'
        val << "-"
        # b is contained in n as n is the string "n-b"
        val << n[2, n.size]
        result = Node.new(:NTH, val)
      elsif n == 'n'
        val << "+"
        val << "0"
        result = Node.new(:NTH, val)
      else
        raise Racc::ParseError, "parse error on IDENT '#{val[1]}'"
      end

    result
end