From: Joel VanderWerf <vjoel@...>
Date: 2003-02-28T07:40:09+09:00
Subject: Re: Looking for shell emulation with command completion

Jim Freeze wrote:
> On Friday, 28 February 2003 at  7:15:50 +0900, Joel VanderWerf wrote:
> 
>>Jim Freeze wrote:
>>
>>>Hi:
>>>
>>>Has anyone written a ruby console app that supports
>>>command completion? I am very interested in
>>>seeing an example of how this can be done.
>>>
>>
>>How about just using irb? It's not hard to extract enough code from the 
>>irb source so you can embed it within your own app. (I'll post the code 
>>if anyone's interested.)
> 
> 
> Never thought about that. Doesn't irb use readline for
> its command completion?

Yes.

>  Please, post the code. I am interested.

=====================================
#!/usr/bin/env ruby

require 'irb'
require 'irb/completion'

module IRB
   def IRB.start_session(object)
     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(object)

     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

     ## might want to reset your app's interrupt handler here
   end
end

if __FILE__ == $0
   class Object
     include IRB::ExtendCommandBundle # so that Marshal.dump works
   end
   x = Object.new
   puts "\nStarted irb shell"
   IRB.start_session(x)
   puts "\nExited irb shell"
end
=======================================

If you want to change the way the x object is displayed in the prompt, 
just define a to_s method for it. Irb lets you customize the prompt, as 
well, but I've never played with that much.