start-irb-from-a-program.rb

# monkey-patch irb.  see: http://jameskilton.com/2009/04/02/embedding-irb-into-your-ruby-application/
#
  require 'irb'

  module IRB # :nodoc:
    def self.start_session(binding)
      unless @__initialized
        args = ARGV
        ARGV.replace(ARGV.dup)
        IRB.setup(nil)
        ARGV.replace(args)
        @__initialized = true
      end
   
      workspace = WorkSpace.new(binding)
   
      irb = Irb.new(workspace)
   
      @CONF[:IRB_RC].call(irb.context) if @CONF[:IRB_RC]
      @CONF[:MAIN_CONTEXT] = irb.context
   
      catch(:IRB_EXIT) do
        irb.eval_input
      end
    end
  end