require 'nkf'module Kconv  AUTO = NKF::AUTO  JIS = NKF::JIS  EUC = NKF::EUC  SJIS = NKF::SJIS  BINARY = NKF::BINARY  NOCONV = NKF::NOCONV  UNKNOWN = NKF::UNKNOWN  def kconv(str, out_code, in_code = AUTO)    opt = '-'    case in_code    when NKF::JIS      opt << 'J'    when NKF::EUC      opt << 'E'    when NKF::SJIS      opt << 'S'    end    case out_code    when NKF::JIS      opt << 'j'    when NKF::EUC      opt << 'e'    when NKF::SJIS      opt << 's'    when NKF::NOCONV      return str    end    opt = '' if opt == '-'    NKF::nkf(opt, str)  end  module_function :kconv  def tojis(str)    NKF::nkf('-j', str)  end  module_function :tojis  def toeuc(str)    NKF::nkf('-e', str)  end  module_function :toeuc  def tosjis(str)    NKF::nkf('-s', str)  end  module_function :tosjis  def guess(str)    NKF::guess(str)  end  module_function :guessendclass String  def kconv(out_code, in_code=Kconv::AUTO)    Kconv::kconv(self, out_code, in_code)  end  def tojis    NKF::nkf('-j', self)  end  def toeuc    NKF::nkf('-e', self)  end  def tosjis    NKF::nkf('-s', self)  endend