nashorn's engine debugging API

[Clément Fauconnier]

Following the discussion started on Twitter, I would like to have more details 
about this API you talked about.
I started doing the exactly same thing adapting JVMDI tty to my needs but it 
was too complicated so I change my approach before viewing how to interact with 
nashorn "compiled" js.
So, I'm really interested to your example. 
Thanks in advance for your reply.
Clément Fauconnier.