class Erubis::Main

def parse_argv(argv, arg_none='', arg_required='', arg_optional='')
  options = {}
  context = {}
  while argv[0] && argv[0][0] == ?-
    optstr = argv.shift
    optstr = optstr[1, optstr.length-1]
    #
    if optstr[0] == ?-    # context
      optstr =~ /\A\-([-\w]+)(?:=(.*))?/  or
        raise CommandOptionError.new("-#{optstr}: invalid context value.")
      name, value = $1, $2
      name  = name.gsub(/-/, '_').intern
      #value = value.nil? ? true : YAML.load(value)   # error, why?
      value = value.nil? ? true : YAML.load("---\n#{value}\n")
      context[name] = value
      #
    else                  # options
      while optstr && !optstr.empty?
        optchar = optstr[0].chr
        optstr = optstr[1..-1]
        if arg_none.include?(optchar)
          options[optchar] = true
        elsif arg_required.include?(optchar)
          arg = optstr.empty? ? argv.shift : optstr  or
            raise CommandOptionError.new("-#{optchar}: #{@option_names[optchar]} required.")
          options[optchar] = arg
          optstr = nil
        elsif arg_optional.include?(optchar)
          arg = optstr.empty? ? true : optstr
          options[optchar] = arg
          optstr = nil
        else
          raise CommandOptionError.new("-#{optchar}: unknown option.")
        end
      end
    end
    #
  end  # end of while
  return options, context
end