# class IRB::Irb

### Constants

CONTROL_CHARACTERS_PATTERN
PROMPT_MAIN_TRUNCATE_LENGTH

  Note: instance and index assignment expressions could also be written like: “foo.bar=(1)” and “foo.[]=(1, bar)”, when expressed that way, the former be parsed as :assign and echo will be suppressed, but the latter is parsed as a :method_add_arg and the output won’t be suppressed

PROMPT_MAIN_TRUNCATE_OMISSION

### Attributes

context[R]

Returns the current context of this irb session

scanner[RW]

The lexer used by this irb session

### Public Class Methods

new(workspace = nil, input_method = nil) click to toggle source

Creates a new irb session

    # File lib/irb.rb, line 934
    def initialize(workspace = nil, input_method = nil)
      @context = Context.new(self, workspace, input_method)
      @context.workspace.load_commands_to_main
      @signal_status = :IN_IRB
      @scanner = RubyLex.new
      @line_no = 1
    end

### Public Instance Methods

build_statement(code) click to toggle source

    # File lib/irb.rb, line 1105
    def build_statement(code)
      code.force_encoding(@context.io.encoding)
      command_or_alias, arg = code.split(/\s/, 2)
      # Transform a non-identifier alias (@, $) or keywords (next, break)
      command_name = @context.command_aliases[command_or_alias.to_sym]
      command = command_name || command_or_alias
      command_class = ExtendCommandBundle.load_command(command)

      if command_class
        Statement::Command.new(code, command, arg, command_class)
      else
        is_assignment_expression = @scanner.assignment_expression?(code, local_variables: @context.local_variables)
        Statement::Expression.new(code, is_assignment_expression)
      end
    end

configure_io() click to toggle source

    # File lib/irb.rb, line 1126
    def configure_io
      if @context.io.respond_to?(:check_termination)
        @context.io.check_termination do |code|
          if Reline::IOGate.in_pasting?
            rest = @scanner.check_termination_in_prev_line(code, local_variables: @context.local_variables)
            if rest
              Reline.delete_text
              rest.bytes.reverse_each do |c|
                Reline.ungetc(c)
              end
              true
            else
              false
            end
          else
            # Accept any single-line input for symbol aliases or commands that transform args
            next true if single_line_command?(code)

            _tokens, _opens, terminated = @scanner.check_code_state(code, local_variables: @context.local_variables)
            terminated
          end
        end
      end
      if @context.io.respond_to?(:dynamic_prompt)
        @context.io.dynamic_prompt do |lines|
          lines << '' if lines.empty?
          tokens = RubyLex.ripper_lex_without_warning(lines.map{ |l| l + "\n" }.join, local_variables: @context.local_variables)
          line_results = IRB::NestingParser.parse_by_line(tokens)
          tokens_until_line = []
          line_results.map.with_index do |(line_tokens, _prev_opens, next_opens, _min_depth), line_num_offset|
            line_tokens.each do |token, _s|
              # Avoid appending duplicated token. Tokens that include "\n" like multiline tstring_content can exist in multiple lines.
              tokens_until_line << token if token != tokens_until_line.last
            end
            continue = @scanner.should_continue?(tokens_until_line)
            generate_prompt(next_opens, continue, line_num_offset)
          end
        end
      end

      if @context.io.respond_to?(:auto_indent) and @context.auto_indent_mode
        @context.io.auto_indent do |lines, line_index, byte_pointer, is_newline|
          next nil if lines == [nil] # Workaround for exit IRB with CTRL+d
          next nil if !is_newline && lines[line_index]&.byteslice(0, byte_pointer)&.match?(/\A\s*\z/)

          code = lines[0..line_index].map { |l| "#{l}\n" }.join
          tokens = RubyLex.ripper_lex_without_warning(code, local_variables: @context.local_variables)
          @scanner.process_indent_level(tokens, lines, line_index, is_newline)
        end
      end
    end

convert_invalid_byte_sequence(str, enc) click to toggle source

    # File lib/irb.rb, line 1178
    def convert_invalid_byte_sequence(str, enc)
      str.force_encoding(enc)
      str.scrub { |c|
        c.bytes.map{ |b| "\\x#{b.to_s(16).upcase}" }.join
      }
    end

debug_break() click to toggle source

A hook point for ‘debug` command’s breakpoint after :IRB_EXIT as well as its clean-up

    # File lib/irb.rb, line 943
    def debug_break
      # it means the debug integration has been activated
      if defined?(DEBUGGER__) && DEBUGGER__.respond_to?(:capture_frames_without_irb)
        # after leaving this initial breakpoint, revert the capture_frames patch
        DEBUGGER__.singleton_class.send(:alias_method, :capture_frames, :capture_frames_without_irb)
        # and remove the redundant method
        DEBUGGER__.singleton_class.send(:undef_method, :capture_frames_without_irb)
      end
    end

debug_readline(binding) click to toggle source

    # File lib/irb.rb, line 953
    def debug_readline(binding)
      workspace = IRB::WorkSpace.new(binding)
      context.workspace = workspace
      context.workspace.load_commands_to_main
      @line_no += 1

      # When users run:
      # 1. Debugging commands, like `step 2`
      # 2. Any input that's not irb-command, like `foo = 123`
      #
      # Irb#eval_input will simply return the input, and we need to pass it to the debugger.
      input = if IRB.conf[:SAVE_HISTORY] && context.io.support_history_saving?
        # Previous IRB session's history has been saved when `Irb#run` is exited
        # We need to make sure the saved history is not saved again by reseting the counter
        context.io.reset_history_counter

        begin
          eval_input
        ensure
          context.io.save_history
        end
      else
        eval_input
      end

      if input&.include?("\n")
        @line_no += input.count("\n") - 1
      end

      input
    end

each_top_level_statement() { |build_statement(code), line_no| ... } click to toggle source

    # File lib/irb.rb, line 1092
    def each_top_level_statement
      loop do
        code = readmultiline
        break unless code

        if code != "\n"
          yield build_statement(code), @line_no
        end
        @line_no += code.count("\n")
      rescue RubyLex::TerminateLineInput
      end
    end

encode_with_invalid_byte_sequence(str, enc) click to toggle source

    # File lib/irb.rb, line 1185
    def encode_with_invalid_byte_sequence(str, enc)
      conv = Encoding::Converter.new(str.encoding, enc)
      dst = String.new
      begin
        ret = conv.primitive_convert(str, dst)
        case ret
        when :invalid_byte_sequence
          conv.insert_output(conv.primitive_errinfo[3].dump[1..-2])
          redo
        when :undefined_conversion
          c = conv.primitive_errinfo[3].dup.force_encoding(conv.primitive_errinfo[1])
          conv.insert_output(c.dump[1..-2])
          redo
        when :incomplete_input
          conv.insert_output(conv.primitive_errinfo[3].dump[1..-2])
        when :finished
        end
        break
      end while nil
      dst
    end

eval_input() click to toggle source

Evaluates input for this session.

    # File lib/irb.rb, line 1012
    def eval_input
      configure_io

      each_top_level_statement do |statement, line_no|
        signal_status(:IN_EVAL) do
          begin
            # If the integration with debugger is activated, we return certain input if it should be dealt with by debugger
            if @context.with_debugger && statement.should_be_handled_by_debugger?
              return statement.code
            end

            @context.evaluate(statement.evaluable_code, line_no)

            if @context.echo? && !statement.suppresses_echo?
              if statement.is_assignment?
                if @context.echo_on_assignment?
                  output_value(@context.echo_on_assignment? == :truncate)
                end
              else
                output_value
              end
            end
          rescue SystemExit, SignalException
            raise
          rescue Interrupt, Exception => exc
            handle_exception(exc)
            @context.workspace.local_variable_set(:_, exc)
          end
        end
      end
    end

handle_exception(exc) click to toggle source

    # File lib/irb.rb, line 1207
    def handle_exception(exc)
      if exc.backtrace[0] =~ /\/irb(2)?(\/.*|-.*|\.rb)?:/ && exc.class.to_s !~ /^IRB/ &&
         !(SyntaxError === exc) && !(EncodingError === exc)
        # The backtrace of invalid encoding hash (ex. {"\xAE": 1}) raises EncodingError without lineno.
        irb_bug = true
      else
        irb_bug = false
      end

      if RUBY_VERSION < '3.0.0'
        if STDOUT.tty?
          message = exc.full_message(order: :bottom)
          order = :bottom
        else
          message = exc.full_message(order: :top)
          order = :top
        end
      else # '3.0.0' <= RUBY_VERSION
        message = exc.full_message(order: :top)
        order = :top
      end
      message = convert_invalid_byte_sequence(message, exc.message.encoding)
      message = encode_with_invalid_byte_sequence(message, IRB.conf[:LC_MESSAGES].encoding) unless message.encoding.to_s.casecmp?(IRB.conf[:LC_MESSAGES].encoding.to_s)
      message = message.gsub(/((?:^\t.+$\n)+)/) { |m|
        case order
        when :top
          lines = m.split("\n")
        when :bottom
          lines = m.split("\n").reverse
        end
        unless irb_bug
          lines = lines.map { |l| @context.workspace.filter_backtrace(l) }.compact
          if lines.size > @context.back_trace_limit
            omit = lines.size - @context.back_trace_limit
            lines = lines[0..(@context.back_trace_limit - 1)]
            lines << "\t... %d levels..." % omit
          end
        end
        lines = lines.reverse if order == :bottom
        lines.map{ |l| l + "\n" }.join
      }
      # The "<top (required)>" in "(irb)" may be the top level of IRB so imitate the main object.
      message = message.gsub(/\(irb\):(?<num>\d+):in `<(?<frame>top \(required\))>'/) { "(irb):#{$~[:num]}:in `<main>'" }
      puts message
      puts 'Maybe IRB bug!' if irb_bug
    rescue Exception => handler_exc
      begin
        puts exc.inspect
        puts "backtraces are hidden because #{handler_exc} was raised when processing them"
      rescue Exception
        puts 'Uninspectable exception occurred'
      end
    end

inspect() click to toggle source

Outputs the local variables to this current session, including `signal_status` and `context`, using `IRB::Locale`.

    # File lib/irb.rb, line 1380
    def inspect
      ary = []
      for iv in instance_variables
        case (iv = iv.to_s)
        when "@signal_status"
          ary.push format("%s=:%s", iv, @signal_status.id2name)
        when "@context"
          ary.push format("%s=%s", iv, eval(iv).__to_s__)
        else
          ary.push format("%s=%s", iv, eval(iv))
        end
      end
      format("#<%s: %s>", self.class, ary.join(", "))
    end

read_input(prompt) click to toggle source

    # File lib/irb.rb, line 1044
    def read_input(prompt)
      signal_status(:IN_INPUT) do
        @context.io.prompt = prompt
        if l = @context.io.gets
          print l if @context.verbose?
        else
          if @context.ignore_eof? and @context.io.readable_after_eof?
            l = "\n"
            if @context.verbose?
              printf "Use \"exit\" to leave %s\n", @context.ap_name
            end
          else
            print "\n" if @context.prompting?
          end
        end
        l
      end
    end

readmultiline() click to toggle source

    # File lib/irb.rb, line 1063
    def readmultiline
      prompt = generate_prompt([], false, 0)

      # multiline
      return read_input(prompt) if @context.io.respond_to?(:check_termination)

      # nomultiline
      code = ''
      line_offset = 0
      loop do
        line = read_input(prompt)
        unless line
          return code.empty? ? nil : code
        end

        code << line

        # Accept any single-line input for symbol aliases or commands that transform args
        return code if single_line_command?(code)

        tokens, opens, terminated = @scanner.check_code_state(code, local_variables: @context.local_variables)
        return code if terminated

        line_offset += 1
        continue = @scanner.should_continue?(tokens)
        prompt = generate_prompt(opens, continue, line_offset)
      end
    end

run(conf = IRB.conf) click to toggle source

    # File lib/irb.rb, line 985
    def run(conf = IRB.conf)
      in_nested_session = !!conf[:MAIN_CONTEXT]
      conf[:IRB_RC].call(context) if conf[:IRB_RC]
      conf[:MAIN_CONTEXT] = context

      save_history = !in_nested_session && conf[:SAVE_HISTORY] && context.io.support_history_saving?

      if save_history
        context.io.load_history
      end

      prev_trap = trap("SIGINT") do
        signal_handle
      end

      begin
        catch(:IRB_EXIT) do
          eval_input
        end
      ensure
        trap("SIGINT", prev_trap)
        conf[:AT_EXIT].each{|hook| hook.call}
        context.io.save_history if save_history
      end
    end

signal_handle() click to toggle source

Handler for the signal SIGINT, see `Kernel#trap` for more information.

    # File lib/irb.rb, line 1307
    def signal_handle
      unless @context.ignore_sigint?
        print "\nabort!\n" if @context.verbose?
        exit
      end

      case @signal_status
      when :IN_INPUT
        print "^C\n"
        raise RubyLex::TerminateLineInput
      when :IN_EVAL
        IRB.irb_abort(self)
      when :IN_LOAD
        IRB.irb_abort(self, LoadAbort)
      when :IN_IRB
        # ignore
      else
        # ignore other cases as well
      end
    end

signal_status(status) { || ... } click to toggle source

Evaluates the given block using the given `status`.

    # File lib/irb.rb, line 1329
    def signal_status(status)
      return yield if @signal_status == :IN_LOAD

      signal_status_back = @signal_status
      @signal_status = status
      begin
        yield
      ensure
        @signal_status = signal_status_back
      end
    end

single_line_command?(code) click to toggle source

    # File lib/irb.rb, line 1121
    def single_line_command?(code)
      command = code.split(/\s/, 2).first
      @context.symbol_alias?(command) || @context.transform_args?(command)
    end

suspend_input_method(input_method) { |back_io| ... } click to toggle source

Evaluates the given block using the given `input_method` as the `Context#io`.

Used by the irb commands `source` and `irb_load`, see IRB Sessions at `IRB` for more information.

    # File lib/irb.rb, line 1296
    def suspend_input_method(input_method)
      back_io = @context.io
      @context.instance_eval{@io = input_method}
      begin
        yield back_io
      ensure
        @context.instance_eval{@io = back_io}
      end
    end

suspend_name(path = nil, name = nil) { |back_path, back_name| ... } click to toggle source

Evaluates the given block using the given `path` as the `Context#irb_path` and `name` as the `Context#irb_name`.

Used by the irb command `source`, see IRB Sessions at `IRB` for more information.

    # File lib/irb.rb, line 1266
    def suspend_name(path = nil, name = nil)
      @context.irb_path, back_path = path, @context.irb_path if path
      @context.irb_name, back_name = name, @context.irb_name if name
      begin
        yield back_path, back_name
      ensure
        @context.irb_path = back_path if path
        @context.irb_name = back_name if name
      end
    end

suspend_workspace(workspace) { |back_workspace| ... } click to toggle source

Evaluates the given block using the given `workspace` as the `Context#workspace`.

Used by the irb command `irb_load`, see IRB Sessions at `IRB` for more information.

    # File lib/irb.rb, line 1282
    def suspend_workspace(workspace)
      @context.workspace, back_workspace = workspace, @context.workspace
      begin
        yield back_workspace
      ensure
        @context.workspace = back_workspace
      end
    end

### Private Instance Methods

generate_prompt(opens, continue, line_offset) click to toggle source

    # File lib/irb.rb, line 1397
    def generate_prompt(opens, continue, line_offset)
      ltype = @scanner.ltype_from_open_tokens(opens)
      indent = @scanner.calc_indent_level(opens)
      continue = opens.any? || continue
      line_no = @line_no + line_offset

      if ltype
        f = @context.prompt_s
      elsif continue
        f = @context.prompt_c
      else
        f = @context.prompt_i
      end
      f = "" unless f
      if @context.prompting?
        p = format_prompt(f, ltype, indent, line_no)
      else
        p = ""
      end
      if @context.auto_indent_mode and !@context.io.respond_to?(:auto_indent)
        unless ltype
          prompt_i = @context.prompt_i.nil? ? "" : @context.prompt_i
          ind = format_prompt(prompt_i, ltype, indent, line_no)[/.*\z/].size +
            indent * 2 - p.size
          p += " " * ind if ind > 0
        end
      end
      p
    end