Module: IRB (Ruby 2.7.2)
Description: Module : IRB - Ruby 2.7.2

### Home Classes Methods

### In Files

- irb.rb
- irb/cmd/chws.rb
- irb/cmd/fork.rb
- irb/cmd/help.rb
- irb/cmd/info.rb
- irb/cmd/load.rb
- irb/cmd/nop.rb
- irb/cmd/pushws.rb
- irb/cmd/subirb.rb
- irb/color.rb
- irb/completion.rb
- irb/context.rb
- irb/easter-egg.rb
- irb/ext/change-ws.rb
- irb/ext/history.rb
- irb/ext/loader.rb
- irb/ext/multi-irb.rb
- irb/ext/save-history.rb
- irb/ext/tracer.rb
- irb/ext/use-loader.rb
- irb/ext/workspaces.rb
- irb/extend-command.rb
- irb/frame.rb
- irb/help.rb
- irb/init.rb
- irb/input-method.rb
- irb/inspector.rb
- irb/lc/error.rb
- irb/lc/ja/encoding_aliases.rb
- irb/lc/ja/error.rb
- irb/locale.rb
- irb/magic-file.rb
- irb/notifier.rb
- irb/output-method.rb
- irb/src_encoding.rb
- irb/version.rb
- irb/workspace.rb
- irb/ws-for-case-2.rb
- irb/xmp.rb

### Namespace

- MODULE IRB::Color
- MODULE IRB::ContextExtender
- MODULE IRB::ExtendCommand
- MODULE IRB::ExtendCommandBundle
- MODULE IRB::IrbLoader
- MODULE IRB::MethodExtender
- MODULE IRB::Notifier
- MODULE IRB::RDoc
- MODULE IRB::Reline
- CLASS IRB::Abort
- CLASS IRB::CantChangeBinding
- CLASS IRB::CantReturnToNormalMode
- CLASS IRB::CantShiftToMultiIrbMode
- CLASS IRB::Canvas
- CLASS IRB::Context
- CLASS IRB::FileInputMethod
- CLASS IRB::Frame
- CLASS IRB::History
- CLASS IRB::IllegalParameter
- CLASS IRB::IllegalRCGenerator
- CLASS IRB::InputMethod
- CLASS IRB::Inspector
- CLASS IRB::Irb
- CLASS IRB::IrbAlreadyDead
- CLASS IRB::IrbSwitchedToCurrentThread
- CLASS IRB::JobManager
- CLASS IRB::LoadAbort
- CLASS IRB::Locale
- CLASS IRB::NoSuchJob
- CLASS IRB::NotImplementedError
- CLASS IRB::OutputMethod
- CLASS IRB::ReadlineInputMethod
- CLASS IRB::ReidlineInputMethod
- CLASS IRB::RubyModel
- CLASS IRB::StdioInputMethod
- CLASS IRB::StdioOutputMethod
- CLASS IRB::UndefinedPromptMode
- CLASS IRB::UnrecognizedSwitch
- CLASS IRB::Vec
- CLASS IRB::WorkSpace

### Methods

- ::CurrentContext
- ::JobManager
- ::conf
- ::default_src_encoding
- ::draw
- ::initialize_tracer
- ::irb
- ::irb_abort
- ::irb_at_exit
- ::irb_exit
- ::print_usage
- ::start
- ::version

### Class/Module Index

Quicksearch

- Binding
- IRB::Abort
- IRB::Canvas
- IRB::Color
- IRB::Color::SymbolState
- IRB::Context
- IRB::ContextExtender
- IRB::ExtendCommandBundle
- IRB::FileInputMethod
- IRB::Frame
- IRB::Frame::FrameOverflow
- IRB::Frame::FrameUnderflow
- IRB::History
- IRB::InputMethod
- IRB::Inspector
- IRB::Irb
- IRB::IrbLoader
- IRB::JobManager
- IRB::LoadAbort
- IRB::MethodExtender
- IRB::Notifier
- IRB::Notifier::AbstractNotifier
- IRB::Notifier::CompositeNotifier
- IRB::Notifier::ErrUndefinedNotifier
- IRB::Notifier::ErrUnrecognizedLevel
- IRB::Notifier::LeveledNotifier
- IRB::Notifier::NoMsgNotifier
- IRB::OutputMethod
- IRB::OutputMethod::NotImplementedError
- IRB::RDoc
- IRB::RDoc::RI
- IRB::ReadlineInputMethod
- IRB::ReidlineInputMethod
- IRB::Reline
- IRB::RubyModel
- IRB::StdioInputMethod
- IRB::StdioOutputMethod
- IRB::Vec
- IRB::WorkSpace
- Object
- XMP
- XMP::StringInputMethod

No matching classes.

# IRB

IRB stands for “interactive Ruby” and is a tool to interactively execute Ruby expressions read from the standard input.

The `irb` command from your shell will start the interpreter.

## Usage¶ ↑

Use of irb is easy if you know Ruby.

When executing irb, prompts are displayed as follows. Then, enter the Ruby expression. An input is executed when it is syntactically complete.

    $ irb
    irb(main):001:0> 1+2
    #=> 3
    irb(main):002:0> class Foo
    irb(main):003:1>  def foo
    irb(main):004:2>    print 1
    irb(main):005:2>  end
    irb(main):006:1> end
    #=> nil

The singleline editor module or multiline editor module can be used with irb. Use of multiline editor is default if it’s installed.

## Command line options¶ ↑

    Usage:  irb.rb [options] [programfile] [arguments]
      -f                Suppress read of ~/.irbrc
      -d                Set $DEBUG to true (same as `ruby -d')
      -r load-module    Same as `ruby -r'
      -I path           Specify $LOAD_PATH directory
      -U                Same as `ruby -U`
      -E enc            Same as `ruby -E`
      -w                Same as `ruby -w`
      -W[level=2]       Same as `ruby -W`
      --inspect         Use `inspect' for output (default except for bc mode)
      --noinspect       Don't use inspect for output
      --multiline       Use multiline editor module
      --nomultiline     Don't use multiline editor module
      --singleline      Use singleline editor module
      --nosingleline    Don't use singleline editor module
      --colorize        Use colorization
      --nocolorize      Don't use colorization
      --prompt prompt-mode
      --prompt-mode prompt-mode
                        Switch prompt mode. Pre-defined prompt modes are
                        `default', `simple', `xmp' and `inf-ruby'
      --inf-ruby-mode   Use prompt appropriate for inf-ruby-mode on emacs.
                        Suppresses --multiline and --singleline.
      --simple-prompt   Simple prompt mode
      --noprompt        No prompt mode
      --tracer          Display trace for each execution of commands.
      --back-trace-limit n
                        Display backtrace top n and tail n. The default
                        value is 16.
      -v, --version     Print the version of irb

## Configuration¶ ↑

IRB reads from `~/.irbrc` when it’s invoked.

If `~/.irbrc` doesn’t exist, `irb` will try to read in the following order:

- `.irbrc`

- `irb.rc`

- `_irbrc`

- `$irbrc`

The following are alternatives to the command line options. To use them type as follows in an `irb` session:

    IRB.conf[:IRB_NAME]="irb"
    IRB.conf[:INSPECT_MODE]=nil
    IRB.conf[:IRB_RC] = nil
    IRB.conf[:BACK_TRACE_LIMIT]=16
    IRB.conf[:USE_LOADER] = false
    IRB.conf[:USE_MULTILINE] = nil
    IRB.conf[:USE_SINGLELINE] = nil
    IRB.conf[:USE_COLORIZE] = true
    IRB.conf[:USE_TRACER] = false
    IRB.conf[:IGNORE_SIGINT] = true
    IRB.conf[:IGNORE_EOF] = false
    IRB.conf[:PROMPT_MODE] = :DEFAULT
    IRB.conf[:PROMPT] = {...}

### Auto indentation¶ ↑

To disable auto-indent mode in irb, add the following to your `.irbrc`:

    IRB.conf[:AUTO_INDENT] = false

### Autocompletion¶ ↑

To enable autocompletion for irb, add the following to your `.irbrc`:

    require 'irb/completion'

### History¶ ↑

By default, irb will store the last 1000 commands you used in `IRB.conf[:HISTORY_FILE]` (`~/.irb_history` by default).

If you want to disable history, add the following to your `.irbrc`:

    IRB.conf[:SAVE_HISTORY] = nil

See IRB::Context#save_history= for more information.

The history of results of commands evaluated is not stored by default, but can be turned on to be stored with this `.irbrc` setting:

    IRB.conf[:EVAL_HISTORY] = <number>

See IRB::Context#eval_history= and History class. The history of command results is not permanently saved in any file.

## Customizing the IRB Prompt¶ ↑

In order to customize the prompt, you can change the following Hash:

    IRB.conf[:PROMPT]

This example can be used in your `.irbrc`

    IRB.conf[:PROMPT][:MY_PROMPT] = { # name of prompt mode
      :AUTO_INDENT => false,          # disables auto-indent mode
      :PROMPT_I =>  ">> ",            # simple prompt
      :PROMPT_S => nil,               # prompt for continuated strings
      :PROMPT_C => nil,               # prompt for continuated statement
      :RETURN => "    ==>%s\n"        # format to return value
    }

    IRB.conf[:PROMPT_MODE] = :MY_PROMPT

Or, invoke irb with the above prompt mode by:

    irb --prompt my-prompt

Constants `PROMPT_I`, `PROMPT_S` and `PROMPT_C` specify the format. In the prompt specification, some special strings are available:

    %N    # command name which is running
    %m    # to_s of main object (self)
    %M    # inspect of main object (self)
    %l    # type of string(", ', /, ]), `]' is inner %w[...]
    %NNi  # indent level. NN is digits and means as same as printf("%NNd").
          # It can be omitted
    %NNn  # line number.
    %%    # %

For instance, the default prompt mode is defined as follows:

    IRB.conf[:PROMPT_MODE][:DEFAULT] = {
      :PROMPT_I => "%N(%m):%03n:%i> ",
      :PROMPT_N => "%N(%m):%03n:%i> ",
      :PROMPT_S => "%N(%m):%03n:%i%l ",
      :PROMPT_C => "%N(%m):%03n:%i* ",
      :RETURN => "%s\n" # used to printf
    }

irb comes with a number of available modes:

    # :NULL:
    #   :PROMPT_I:
    #   :PROMPT_N:
    #   :PROMPT_S:
    #   :PROMPT_C:
    #   :RETURN: |
    #     %s
    # :DEFAULT:
    #   :PROMPT_I: ! '%N(%m):%03n:%i> '
    #   :PROMPT_N: ! '%N(%m):%03n:%i> '
    #   :PROMPT_S: ! '%N(%m):%03n:%i%l '
    #   :PROMPT_C: ! '%N(%m):%03n:%i* '
    #   :RETURN: |
    #     => %s
    # :CLASSIC:
    #   :PROMPT_I: ! '%N(%m):%03n:%i> '
    #   :PROMPT_N: ! '%N(%m):%03n:%i> '
    #   :PROMPT_S: ! '%N(%m):%03n:%i%l '
    #   :PROMPT_C: ! '%N(%m):%03n:%i* '
    #   :RETURN: |
    #     %s
    # :SIMPLE:
    #   :PROMPT_I: ! '>> '
    #   :PROMPT_N: ! '>> '
    #   :PROMPT_S:
    #   :PROMPT_C: ! '?> '
    #   :RETURN: |
    #     => %s
    # :INF_RUBY:
    #   :PROMPT_I: ! '%N(%m):%03n:%i> '
    #   :PROMPT_N:
    #   :PROMPT_S:
    #   :PROMPT_C:
    #   :RETURN: |
    #     %s
    #   :AUTO_INDENT: true
    # :XMP:
    #   :PROMPT_I:
    #   :PROMPT_N:
    #   :PROMPT_S:
    #   :PROMPT_C:
    #   :RETURN: |2
    #         ==>%s

## Restrictions¶ ↑

Because irb evaluates input immediately after it is syntactically complete, the results may be slightly different than directly using Ruby.

## IRB Sessions¶ ↑

IRB has a special feature, that allows you to manage many sessions at once.

You can create new sessions with Irb.irb, and get a list of current sessions with the `jobs` command in the prompt.

### Commands¶ ↑

JobManager provides commands to handle the current sessions:

    jobs    # List of current sessions
    fg      # Switches to the session of the given number
    kill    # Kills the session with the given number

The `exit` command, or ::irb_exit, will quit the current session and call any exit hooks with ::irb_at_exit.

A few commands for loading files within the session are also available:

`source`

  Loads a given file in the current session and displays the source lines, see IRB::IrbLoader#source_file

`irb_load`

  Loads the given file similarly to Kernel#load, see IRB::IrbLoader#irb_load

`irb_require`

  Loads the given file similarly to Kernel#require

### Configuration¶ ↑

The command line options, or ::conf, specify the default behavior of Irb.irb.

On the other hand, each conf in IRB is used to individually configure ::irb.

If a proc is set for `IRB.conf[:IRB_RC]`, its will be invoked after execution of that proc with the context of the current session as its argument. Each session can be configured using this mechanism.

### Session variables¶ ↑

There are a few variables in every Irb session that can come in handy:

`_`

  The value command executed, as a local variable

`__`

  The history of evaluated commands. Available only if `IRB.conf[:EVAL_HISTORY]` is not `nil` (which is the default). See also IRB::Context#eval_history= and IRB::History.

`__[line_no]`

  Returns the evaluation value at the given line number, `line_no`. If `line_no` is a negative, the return value `line_no` many lines before the most recent return value.

### Example using IRB Sessions¶ ↑

    # invoke a new session
    irb(main):001:0> irb
    # list open sessions
    irb.1(main):001:0> jobs
      #0->irb on main (#<Thread:0x400fb7e4> : stop)
      #1->irb#1 on main (#<Thread:0x40125d64> : running)

    # change the active session
    irb.1(main):002:0> fg 0
    # define class Foo in top-level session
    irb(main):002:0> class Foo;end
    # invoke a new session with the context of Foo
    irb(main):003:0> irb Foo
    # define Foo#foo
    irb.2(Foo):001:0> def foo
    irb.2(Foo):002:1>   print 1
    irb.2(Foo):003:1> end

    # change the active session
    irb.2(Foo):004:0> fg 0
    # list open sessions
    irb(main):004:0> jobs
      #0->irb on main (#<Thread:0x400fb7e4> : running)
      #1->irb#1 on main (#<Thread:0x40125d64> : stop)
      #2->irb#2 on Foo (#<Thread:0x4011d54c> : stop)
    # check if Foo#foo is available
    irb(main):005:0> Foo.instance_methods #=> [:foo, ...]

    # change the active session
    irb(main):006:0> fg 2
    # define Foo#bar in the context of Foo
    irb.2(Foo):005:0> def bar
    irb.2(Foo):006:1>  print "bar"
    irb.2(Foo):007:1> end
    irb.2(Foo):010:0>  Foo.instance_methods #=> [:bar, :foo, ...]

    # change the active session
    irb.2(Foo):011:0> fg 0
    irb(main):007:0> f = Foo.new  #=> #<Foo:0x4010af3c>
    # invoke a new session with the context of f (instance of Foo)
    irb(main):008:0> irb f
    # list open sessions
    irb.3(<Foo:0x4010af3c>):001:0> jobs
      #0->irb on main (#<Thread:0x400fb7e4> : stop)
      #1->irb#1 on main (#<Thread:0x40125d64> : stop)
      #2->irb#2 on Foo (#<Thread:0x4011d54c> : stop)
      #3->irb#3 on #<Foo:0x4010af3c> (#<Thread:0x4010a1e0> : running)
    # evaluate f.foo
    irb.3(<Foo:0x4010af3c>):002:0> foo #=> 1 => nil
    # evaluate f.bar
    irb.3(<Foo:0x4010af3c>):003:0> bar #=> bar => nil
    # kill jobs 1, 2, and 3
    irb.3(<Foo:0x4010af3c>):004:0> kill 1, 2, 3
    # list open sessions, should only include main session
    irb(main):009:0> jobs
      #0->irb on main (#<Thread:0x400fb7e4> : running)
    # quit irb
    irb(main):010:0> exit

frozen_string_literal: false

    save-history.rb -
        $Release Version: 0.9.6$
        $Revision$
        by Keiju ISHITSUKA(keiju@ruby-lang.org)

–

frozen_string_literal: false

    frame.rb -
        $Release Version: 0.9$
        $Revision$
        by Keiju ISHITSUKA(Nihon Rational Software Co.,Ltd)

–

frozen_string_literal: false

frozen_string_literal: false

    output-method.rb - output methods used by irb
        $Release Version: 0.9.6$
        $Revision$
        by Keiju ISHITSUKA(keiju@ruby-lang.org)

–

frozen_string_literal: false DO NOT WRITE ANY MAGIC COMMENT HERE.

### Constants

TracerLoadError

### Public Class Methods

CurrentContext() click to toggle source

The current IRB::Context of the session, see ::conf

    irb
    irb(main):001:0> IRB.CurrentContext.irb_name = "foo"
    foo(main):002:0> IRB.conf[:MAIN_CONTEXT].irb_name #=> "foo"

                   # File irb.rb, line 384
    def IRB.CurrentContext
      IRB.conf[:MAIN_CONTEXT]
    end

JobManager() click to toggle source

The current JobManager in the session

                   # File irb/ext/multi-irb.rb, line 176
    def IRB.JobManager
      @JobManager
    end

conf() click to toggle source

Displays current configuration.

Modifying the configuration is achieved by sending a message to ::conf.

See Configuration at IRB for more information.

                   # File irb.rb, line 367
    def IRB.conf
      @CONF
    end

default_src_encoding() click to toggle source

                   # File irb/src_encoding.rb, line 4
    def self.default_src_encoding
      return __ENCODING__
    end

draw() click to toggle source

                   # File irb/easter-egg.rb, line 55
    def draw
      @data.each {|row| row.fill(0) }
      yield
      @data.map {|row| row.map {|n| " ',;"[n] }.join }.join("\n")
    end

initialize_tracer() click to toggle source

initialize tracing function

                   # File irb/ext/tracer.rb, line 30
    def IRB.initialize_tracer
      Tracer.verbose = false
      Tracer.add_filter {
        |event, file, line, id, binding, *rests|
        /^#{Regexp.quote(@CONF[:IRB_LIB_PATH])}/ !~ file and
          File::basename(file) != "irb.rb"
      }
    end

irb(file = nil, *main) click to toggle source

Creates a new IRB session, see IRB::Irb.new.

The optional `file` argument is given to IRB::Context.new, along with the workspace created with the remaining arguments, see IRB::WorkSpace.new

                   # File irb/ext/multi-irb.rb, line 189
    def IRB.irb(file = nil, *main)
      workspace = WorkSpace.new(*main)
      parent_thread = Thread.current
      Thread.start do
        begin
          irb = Irb.new(workspace, file)
        rescue
          print "Subirb can't start with context(self): ", workspace.main.inspect, "\n"
          print "return to main irb\n"
          Thread.pass
          Thread.main.wakeup
          Thread.exit
        end
        @CONF[:IRB_RC].call(irb.context) if @CONF[:IRB_RC]
        @JobManager.insert(irb)
        @JobManager.current_job = irb
        begin
          system_exit = false
          catch(:IRB_EXIT) do
            irb.eval_input
          end
        rescue SystemExit
          system_exit = true
          raise
          #fail
        ensure
          unless system_exit
            @JobManager.delete(irb)
            if @JobManager.current_job == irb
              if parent_thread.alive?
                @JobManager.current_job = @JobManager.irb(parent_thread)
                parent_thread.run
              else
                @JobManager.current_job = @JobManager.main_irb
                @JobManager.main_thread.run
              end
            end
          end
        end
      end
      Thread.stop
      @JobManager.current_job = @JobManager.irb(Thread.current)
    end

irb_abort(irb, exception = Abort) click to toggle source

Aborts then interrupts irb.

Will raise an Abort exception, or the given `exception`.

                   # File irb.rb, line 416
    def IRB.irb_abort(irb, exception = Abort)
      if defined? Thread
        irb.context.thread.raise exception, "abort then interrupt!"
      else
        raise exception, "abort then interrupt!"
      end
    end

irb_at_exit() click to toggle source

Calls each event hook of `IRB.conf[:TA_EXIT]` when the current session quits.

                   # File irb.rb, line 404
    def IRB.irb_at_exit
      @CONF[:AT_EXIT].each{|hook| hook.call}
    end

irb_exit(irb, ret) click to toggle source

Quits irb

                   # File irb.rb, line 409
    def IRB.irb_exit(irb, ret)
      throw :IRB_EXIT, ret
    end

print_usage() click to toggle source

Outputs the irb help message, see Command line options at IRB.

                   # File irb/help.rb, line 17
    def IRB.print_usage
      lc = IRB.conf[:LC_MESSAGES]
      path = lc.find("irb/help-message")
      space_line = false
      IRB::MagicFile.open(path){|f|
        f.each_line do |l|
          if /^\s*$/ =~ l
            lc.puts l unless space_line
            space_line = true
            next
          end
          space_line = false

          l.sub!(/#.*$/, "")
          next if /^\s*$/ =~ l
          lc.puts l
        end
      }
    end

start(ap_path = nil) click to toggle source

Initializes IRB and creates a new Irb.irb object at the `TOPLEVEL_BINDING`

                   # File irb.rb, line 389
    def IRB.start(ap_path = nil)
      STDOUT.sync = true
      $0 = File::basename(ap_path, ".rb") if ap_path

      IRB.setup(ap_path)

      if @CONF[:SCRIPT]
        irb = Irb.new(nil, @CONF[:SCRIPT])
      else
        irb = Irb.new
      end
      irb.run(@CONF)
    end

version() click to toggle source

Returns the current version of IRB, including release version and last updated date.

                   # File irb.rb, line 373
    def IRB.version
      if v = @CONF[:VERSION] then return v end

      @CONF[:VERSION] = format("irb %s (%s)", @RELEASE_VERSION, @LAST_UPDATE_DATE)
    end