From: Joel VanderWerf <vjoel@...>
Date: 2002-06-14T06:21:22+09:00
Subject: Re: Embedding irb

Gilles Filippini wrote:
> 
> Hi,
> 
> It must be a basic question, but I didn't find any answer:
> How to embed an IRB session into a ruby app ?

This is one way to do it for a command line app (i.e., without changing
stdin/out). It works well, but I do wish IRB made this a bit easier. The
obj argument to start_session will be self when the session starts up.

require 'irb'
require 'irb/completion'

module IRB
  def IRB.start_session(obj)
    unless $irb
      IRB.initialize nil
      ## maybe set some opts here, as in parse_opts in irb/init.rb?
      IRB.load_modules
    end
    
    workspace = WorkSpace.new(obj)

    if @CONF[:SCRIPT] ## normally, set by parse_opts
      $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("INT") do
      $irb.signal_handle
    end

    catch(:IRB_EXIT) do
      $irb.eval_input
    end
    print "\n"
    
    ## might want to reset your app's interrupt handler here
  end
end