Collection of IRB tricks

drop-to-irb.rb

require 'irb'

module IRB
  def self.start_session(binding)
    IRB.setup(nil)

    workspace = WorkSpace.new(binding)

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

    @CONF[:IRB_RC].call(irb.context) if @CONF[:IRB_RC]
    @CONF[:MAIN_CONTEXT] = irb.context

    trap("SIGINT") do
      irb.signal_handle
    end

    catch(:IRB_EXIT) do
      irb.eval_input
    end
  end
end

# we want to manipulate this in IRB
two = 1 + 1

IRB.start_session(Kernel.binding)


### Example Session:
# $ ruby debug.rb 
# >> two
# => 2
# >> three
# NameError: undefined local variable or method `three' for Kernel:Module
#         from (irb):1
#         from debug.rb:31

irb-tips.rb

# Tab-completion using readline
require 'irb/completion'
ARGV.concat [ "--readline", "--prompt-mode", "simple" ]

# persistent IRB command history
require 'irb/ext/save-history'
IRB.conf[:SAVE_HISTORY] = 100
IRB.conf[:HISTORY_FILE] = "#{ENV['HOME']}/.irb-save-history"

# Simpler prompt
IRB.conf[:PROMPT_MODE] = :SIMPLE

# Dr. Nic's .irbrc:
require 'irb/completion'        # Tab-completion
require 'map_by_method'         # Mapping by method (a.map_to_s = a.map &:to_s)
require 'what_methods'          # MethodFinder
require 'pp'                    # Pretty-printing
IRB.conf[:AUTO_INDENT]=true     # Auto indentation

# Execute file every time it changes
def loop_execute(file)
  old_mtime = nil
  loop do
    # print("\e[sWaiting...")
    sleep(0.2) while (mtime = File.stat(file).mtime) == old_mtime
    # print("\e[u\e[K")
    begin
      r = eval(File.read(file))
      puts("=> #{r.inspect}")
    rescue IRB::Abort
      puts("Abort")
      return
    rescue Exception => e
      puts("#{e.class}: #{e.message}\n#{e.backtrace.join("\n")}")
    end
    old_mtime = mtime
  end
end

shell-from-irb.rb

# Running shell commands from inside IRB
# Based on <http://woss.name/2006/07/12/using-the-shell-within-irb/> by:
# Graeme Mathieson
require 'shell'

# Override the command processor widget for inserting system commands so
# that it behaves more like path-processing: earlier commands take precedence.
require 'shell/command-processor'
module FixAddDelegateCommandToShell
  def self.extended(obj)
    class << obj
      alias_method :add_delegate_command_to_shell_override, :add_delegate_command_to_shell unless method_defined?(:add_delegate_command_to_shell_override)
      alias_method :add_delegate_command_to_shell, :add_delegate_command_to_shell_no_override
    end
  end

  def add_delegate_command_to_shell_no_override(id)
    id = id.intern if id.kind_of?(String)
    name = id.id2name
    if Shell.method_defined?(id) or Shell::Filter.method_defined?(id)
      Shell.notify "warn: Not overriding existing definition of Shell##{name}."
    else
      add_delegate_command_to_shell_override(id)
    end
  end
end
Shell::CommandProcessor.extend(FixAddDelegateCommandToShell)

# Allow Shell system commands to take :symbols too, to save a little typing.
require 'shell/system-command'
class Shell
  class SystemCommand
    alias_method :initialize_orig, :initialize
    def initialize(sh, command, *opts)
      opts.collect! {|opt| opt.to_s }
      initialize_orig sh, command, *opts
    end
  end
end

# Provide me with a shell inside IRB to save quitting and restarting, or
# finding that other terminal window.
def shell
  unless $shell
    verbose = Shell.verbose
    Shell.verbose = false
    Shell.install_system_commands '' # no prefix
    $shell = Shell.new
    Shell.verbose = verbose
  end
  $shell
end