# class IRB::Irb

### Constants

ATTR_PLAIN
ATTR_TTY

### 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, output_method = nil) click to toggle source

Creates a new irb session

    # File lib/irb.rb, line 409
    def initialize(workspace = nil, input_method = nil, output_method = nil)
      @context = Context.new(self, workspace, input_method, output_method)
      @context.main.extend ExtendCommandBundle
      @signal_status = :IN_IRB

      @scanner = RubyLex.new
      @scanner.exception_on_syntax_error = false
    end

### Public Instance Methods

eval_input() click to toggle source

Evaluates input for this session.

    # File lib/irb.rb, line 441
    def eval_input
      exc = nil

      @scanner.set_prompt do
        |ltype, indent, continue, line_no|
        if ltype
          f = @context.prompt_s
        elsif continue
          f = @context.prompt_c
        elsif indent > 0
          f = @context.prompt_n
        else
          f = @context.prompt_i
        end
        f = "" unless f
        if @context.prompting?
          @context.io.prompt = p = prompt(f, ltype, indent, line_no)
        else
          @context.io.prompt = p = ""
        end
        if @context.auto_indent_mode
          unless ltype
            ind = prompt(@context.prompt_i, ltype, indent, line_no)[/.*\z/].size +
              indent * 2 - p.size
            ind += 2 if continue
            @context.io.prompt = p + " " * ind if ind > 0
          end
        end
      end

      @scanner.set_input(@context.io) do
        signal_status(:IN_INPUT) do
          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"
            end
          end
          l
        end
      end

      @scanner.each_top_level_statement do |line, line_no|
        signal_status(:IN_EVAL) do
          begin
            line.untaint
            @context.evaluate(line, line_no, exception: exc)
            output_value if @context.echo?
          rescue Interrupt => exc
          rescue SystemExit, SignalException
            raise
          rescue Exception => exc
          else
            exc = nil
            next
          end
          handle_exception(exc)
        end
      end
    end

handle_exception(exc) click to toggle source

    # File lib/irb.rb, line 508
    def handle_exception(exc)
      if exc.backtrace && exc.backtrace[0] =~ /irb(2)?(\/.*|-.*|\.rb)?:/ && exc.class.to_s !~ /^IRB/ &&
         !(SyntaxError === exc)
        irb_bug = true
      else
        irb_bug = false
      end

      if STDOUT.tty?
        attr = ATTR_TTY
        print "#{attr[1]}Traceback#{attr[]} (most recent call last):\n"
      else
        attr = ATTR_PLAIN
      end
      messages = []
      lasts = []
      levels = 0
      if exc.backtrace
        count = 0
        exc.backtrace.each do |m|
          m = @context.workspace.filter_backtrace(m) or next unless irb_bug
          count += 1
          if attr == ATTR_TTY
            m = sprintf("%9d: from %s", count, m)
          else
            m = "\tfrom #{m}"
          end
          if messages.size < @context.back_trace_limit
            messages.push(m)
          elsif lasts.size < @context.back_trace_limit
            lasts.push(m).shift
            levels += 1
          end
        end
      end
      if attr == ATTR_TTY
        unless lasts.empty?
          puts lasts.reverse
          printf "... %d levels...\n", levels if levels > 0
        end
        puts messages.reverse
      end
      m = exc.to_s.split(/\n/)
      print "#{attr[1]}#{exc.class} (#{attr[4]}#{m.shift}#{attr[0, 1]})#{attr[]}\n"
      puts m.map {|s| "#{attr[1]}#{s}#{attr[]}\n"}
      if attr == ATTR_PLAIN
        puts messages
        unless lasts.empty?
          puts lasts
          printf "... %d levels...\n", levels if levels > 0
        end
      end
      print "Maybe IRB bug!\n" if irb_bug
    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 690
    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

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

    # File lib/irb.rb, line 418
    def run(conf = IRB.conf)
      conf[:IRB_RC].call(context) if conf[:IRB_RC]
      conf[:MAIN_CONTEXT] = context

      trap("SIGINT") do
        signal_handle
      end

      begin
        catch(:IRB_EXIT) do
          eval_input
        end
      ensure
        conf[:AT_EXIT].each{|hook| hook.call}
      end
    end

signal_handle() click to toggle source

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

    # File lib/irb.rb, line 619
    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 641
    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

suspend_context(context) { |back_context| ... } click to toggle source

Evaluates the given block using the given `context` as the `Context`.

    # File lib/irb.rb, line 609
    def suspend_context(context)
      @context, back_context = context, @context
      begin
        yield back_context
      ensure
        @context = back_context
      end
    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 598
    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 568
    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 584
    def suspend_workspace(workspace)
      @context.workspace, back_workspace = workspace, @context.workspace
      begin
        yield back_workspace
      ensure
        @context.workspace = back_workspace
      end
    end