def option_set ( opt_form, opt_app )
      if opt_app.param then
	# option parameter buit-in option name by '='
	if opt_form[:n].include? '=' then
	  opt_app.value = opt_form[:n].split('=')[-1]
	  return ''
	end
	# option parameter buit-in option name
	if opt_form[:t] == OPTION_PREFIX_SHORT and
	   opt_form[:n].length > opt_app.shortname.length then
	  opt_app.value = opt_form[:n][opt_app.shortname.length, opt_form[:n].length - opt_app.shortname.length]
	  return ''
	end
	# option parameter present in next ARGV.
	if opt_form[:i].next >= ARGV.size then
          puts "fatal error: unable to find argument for option '#{opt_form[:n]}'."
          exit
	end
	# if next argument is a option.
	arg = ARGV[opt_form[:i].next]
        if getopt( arg )[:n] != '' then
          puts "fatal error: miss argument for option '#{opt_form[:t]}#{opt_form[:n]}'."
          exit
        end
	opt_app.value = arg
	return arg
      else
	opt_app.value = true
      end
      return ''
    end
def option_set ( opt_form, opt_app )
      if opt_app.param then
	# option parameter buit-in option name by '='
	if opt_form[:n].include? '=' then
	  opt_app.value = opt_form[:n].split('=')[-1]
	  return ''
	end
	# option parameter buit-in option name
	if opt_form[:t] == OPTION_PREFIX_SHORT and
	   opt_form[:n].length > opt_app.shortname.length then
	  opt_app.value = opt_form[:n][opt_app.shortname.length, opt_form[:n].length - opt_app.shortname.length]
	  return ''
	end
	# option parameter present in next ARGV.
	if opt_form[:i].next >= ARGV.size then
          puts "fatal error: unable to find argument for option '#{opt_form[:n]}'."
          exit
	end
	# if next argument is a option.
	arg = ARGV[opt_form[:i].next]
        if getopt( arg )[:n] != '' then
          puts "fatal error: miss argument for option '#{opt_form[:t]}#{opt_form[:n]}'."
          exit
        end
	opt_app.value = arg
	return arg
      else
	opt_app.value = true
      end
      return ''
    end
Set application option object.
 opt_form -- object formed by getopt.
 opt_app  -- application option object.
 Return delete name in ARGV or ''.