parse_opts

# File lib/irb/init.rb, line 124
  def IRB.parse_opts(argv: ::ARGV)
    load_path = []
    while opt = argv.shift
      case opt
      when "-f"
        @CONF[:RC] = false
      when "-d"
        $DEBUG = true
        $VERBOSE = true
      when "-w"
        $VERBOSE = true
      when /^-W(.+)?/
        opt = $1 || argv.shift
        case opt
        when "0"
          $VERBOSE = nil
        when "1"
          $VERBOSE = false
        else
          $VERBOSE = true
        end
      when /^-r(.+)?/
        opt = $1 || argv.shift
        @CONF[:LOAD_MODULES].push opt if opt
      when /^-I(.+)?/
        opt = $1 || argv.shift
        load_path.concat(opt.split(File::PATH_SEPARATOR)) if opt
      when '-U'
        set_encoding("UTF-8", "UTF-8")
      when /^-E(.+)?/, /^--encoding(?:=(.+))?/
        opt = $1 || argv.shift
        set_encoding(*opt.split(':', 2))
      when "--inspect"
        if /^-/ !~ argv.first
          @CONF[:INSPECT_MODE] = argv.shift
        else
          @CONF[:INSPECT_MODE] = true
        end
      when "--noinspect"
        @CONF[:INSPECT_MODE] = false
      when "--readline"
        @CONF[:USE_READLINE] = true
      when "--noreadline"
        @CONF[:USE_READLINE] = false
      when "--echo"
        @CONF[:ECHO] = true
      when "--noecho"
        @CONF[:ECHO] = false
      when "--verbose"
        @CONF[:VERBOSE] = true
      when "--noverbose"
        @CONF[:VERBOSE] = false
      when /^--prompt-mode(?:=(.+))?/, /^--prompt(?:=(.+))?/
        opt = $1 || argv.shift
        prompt_mode = opt.upcase.tr("-", "_").intern
        @CONF[:PROMPT_MODE] = prompt_mode
      when "--noprompt"
        @CONF[:PROMPT_MODE] = :NULL
      when "--inf-ruby-mode"
        @CONF[:PROMPT_MODE] = :INF_RUBY
      when "--sample-book-mode", "--simple-prompt"
        @CONF[:PROMPT_MODE] = :SIMPLE
      when "--tracer"
        @CONF[:USE_TRACER] = true
      when /^--back-trace-limit(?:=(.+))?/
        @CONF[:BACK_TRACE_LIMIT] = ($1 || argv.shift).to_i
      when /^--context-mode(?:=(.+))?/
        @CONF[:CONTEXT_MODE] = ($1 || argv.shift).to_i
      when "--single-irb"
        @CONF[:SINGLE_IRB] = true
      when /^--irb_debug(?:=(.+))?/
        @CONF[:DEBUG_LEVEL] = ($1 || argv.shift).to_i
      when "-v", "--version"
        print IRB.version, "\n"
        exit 0
      when "-h", "--help"
        require_relative "help"
        IRB.print_usage
        exit 0
      when "--"
        if opt = argv.shift
          @CONF[:SCRIPT] = opt
          $0 = opt
        end
        break
      when /^-/
        IRB.fail UnrecognizedSwitch, opt
      else
        @CONF[:SCRIPT] = opt
        $0 = opt
        break
      end
    end
    load_path.collect! do |path|
      /\A\.\// =~ path ? path : File.expand_path(path)
    end
    $LOAD_PATH.unshift(*load_path)

  end